World Trade Center
Overview
 
The original World Trade Center was a complex with seven buildings featuring landmark twin towers in Lower Manhattan
Lower Manhattan
Lower Manhattan is the southernmost part of the island of Manhattan, the main island and center of business and government of the City of New York...

, New York City
New York City
New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...

, United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. The complex opened on April 4, 1973, and was destroyed in 2001 during the September 11 attacks. The site is currently being rebuilt with five new skyscrapers and a memorial to the casualties of the attacks. , only one skyscraper has been completed
7 World Trade Center
7 World Trade Center is a building in New York City located across from the World Trade Center site in Lower Manhattan. It is the second building to bear that name and address in that location. The original structure was completed in 1987 and was destroyed in the September 11 attacks...

, with four more expected to be completed before 2020. One World Trade Center will be the lead building for the new complex and is expected to be finished by 2013.
Unanswered Questions
Encyclopedia
The original World Trade Center was a complex with seven buildings featuring landmark twin towers in Lower Manhattan
Lower Manhattan
Lower Manhattan is the southernmost part of the island of Manhattan, the main island and center of business and government of the City of New York...

, New York City
New York City
New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...

, United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. The complex opened on April 4, 1973, and was destroyed in 2001 during the September 11 attacks. The site is currently being rebuilt with five new skyscrapers and a memorial to the casualties of the attacks. , only one skyscraper has been completed
7 World Trade Center
7 World Trade Center is a building in New York City located across from the World Trade Center site in Lower Manhattan. It is the second building to bear that name and address in that location. The original structure was completed in 1987 and was destroyed in the September 11 attacks...

, with four more expected to be completed before 2020. One World Trade Center will be the lead building for the new complex and is expected to be finished by 2013. A sixth tower is still awaiting confirmation to be built. At the time of their completion, the original 1 and 2 World Trade Center were the tallest buildings in the world.

The complex was designed in the early 1960s by Minoru Yamasaki
Minoru Yamasaki
was a Japanese-American architect, best known for his design of the twin towers of the World Trade Center, buildings 1 and 2. Yamasaki was one of the most prominent architects of the 20th century...

 and Associates of Troy, Michigan, and Emery Roth and Sons of New York. The twin 110-story towers used a tube-frame structural design
Tube (structure)
In structural engineering, the tube is the name given to the systems where in order to resist lateral loads a building is designed to act like a three-dimensional hollow tube, cantilevered perpendicular to the ground. The system was introduced by Fazlur Rahman Khan while at Skidmore, Owings and...

. To gain approval for the project, the Port Authority of New York and New Jersey
Port Authority of New York and New Jersey
The Port Authority of New York and New Jersey is a bi-state port district, established in 1921 through an interstate compact, that runs most of the regional transportation infrastructure, including the bridges, tunnels, airports, and seaports, within the Port of New York and New Jersey...

 agreed to take over the Hudson & Manhattan Railroad, which became the Port Authority Trans-Hudson
Port Authority Trans-Hudson
PATH, derived from Port Authority Trans-Hudson, is a rapid transit railroad linking Manhattan, New York City with Newark, Harrison, Hoboken and Jersey City in metropolitan northern New Jersey...

 (PATH). Groundbreaking for the World Trade Center took place on , 1966. The North Tower (1) was completed in and the South Tower (2) was finished in . The construction project
Construction of the World Trade Center
The construction of the World Trade Center was conceived as an urban renewal project, spearheaded by David Rockefeller, to help revitalize Lower Manhattan. The project was developed by the Port Authority of New York and New Jersey, which hired architect Minoru Yamasaki who came up with the specific...

 involved excavating a large amount of material, which was later used as landfill to build Battery Park City on the west side of Lower Manhattan. The cost for the construction was $400 million ($ in dollars).
The complex was located in the heart of New York City's downtown financial district and contained 13.4 million square feet (1.24 million m2) of office space. The Windows on the World
Windows on the World
Windows on the World was a complex of venues at the top floors of the North Tower of the World Trade Center in Lower Manhattan that included a restaurant, Windows on the World, a smaller restaurant called Wild Blue, and a bar called The Greatest Bar on Earth, as well as rooms for private functions...

 restaurant was located on the 106th and 107th floors of 1 World Trade Center (the North Tower) while the Top of the World observation deck was located on the 107th floor of 2 World Trade Center (the South Tower). Other World Trade Center buildings included the Marriott World Trade Center; 4 World Trade Center; 5 World Trade Center; 6 World Trade Center, which housed the United States Customs. All of these buildings were built between 1975 and 1981. The final building constructed was 7 World Trade Center, which was built in 1985. The second King Kong
King Kong (1976 film)
King Kong is a 1976 American monster movie produced by Dino De Laurentiis and directed by John Guillermin. It is a remake of the 1933 classic film of the same name, about a giant ape that is captured and imported to New York City for exhibition....

was filmed in 1976 with some scenes mentioning and showing the World Trade Center. The World Trade Center experienced a fire on , 1975, and a bombing
1993 World Trade Center bombing
The 1993 World Trade Center bombing occurred on February 26, 1993, when a truck bomb was detonated below the North Tower of the World Trade Center in New York City. The 1,336 lb urea nitrate–hydrogen gas enhanced device was intended to knock the North Tower into the South Tower , bringing...

 on , 1993. In 1998, the Port Authority decided to privatize the World Trade Center, leasing the buildings to a private company to manage, and awarded the lease to Silverstein Properties in .

On the morning of September 11, 2001, Al-Qaeda
Al-Qaeda
Al-Qaeda is a global broad-based militant Islamist terrorist organization founded by Osama bin Laden sometime between August 1988 and late 1989. It operates as a network comprising both a multinational, stateless army and a radical Sunni Muslim movement calling for global Jihad...

-affiliated hijackers flew two 767
Boeing 767
The Boeing 767 is a mid-size, wide-body twin-engine jet airliner built by Boeing Commercial Airplanes. It was the manufacturer's first wide-body twinjet and its first airliner with a two-crew glass cockpit. The aircraft features two turbofan engines, a supercritical wing, and a conventional tail...

 jets into the complex, one into each tower, in a coordinated terrorist attack. After burning for 56 minutes, the South Tower (2) collapsed, followed a half-hour later by the North Tower (1), with the attacks on the World Trade Center resulting in 2,753 deaths. 7 World Trade Center collapsed later in the day and the other buildings, although they did not collapse, had to be demolished because they were damaged beyond repair. The process of cleanup and recovery at the World Trade Center site
World Trade Center site
The World Trade Center site , also known as "Ground Zero" after the September 11 attacks, sits on in Lower Manhattan in New York City...

 took eight months. The first new building at the site was 7 World Trade Center, which opened in . The Lower Manhattan Development Corporation
Lower Manhattan Development Corporation
The Lower Manhattan Development Corporation was formed in July 2002, after the September 11 attacks to plan the reconstruction of Lower Manhattan and distribute nearly $10 billion in federal funds aimed at rebuilding downtown Manhattan....

 (LMDC), established in to oversee the rebuilding process, organized competitions to select a site plan
Site plan
A site plan is an architectural plan, landscape architecture document, and a detailed engineering drawing of proposed improvements to a given lot...

 and memorial design. Memory Foundations
Memory Foundations
Memory Foundations is the name given by Daniel Libeskind to his site plan for the World Trade Center, which was selected by the Lower Manhattan Development Corporation to be the master plan for rebuilding at the World Trade Center site in New York City....

, designed by Daniel Libeskind
Daniel Libeskind
Daniel Libeskind, is an American architect, artist, and set designer of Polish-Jewish descent. Libeskind founded Studio Daniel Libeskind in 1989 with his wife, Nina, and is its principal design architect...

, was selected as the master plan, which included the 1776 feet (541 m) One World Trade Center, three office towers along Church Street and a memorial designed by Michael Arad
Michael Arad
Michael Arad is an Israeli-American architect who best known for being the designer of the World Trade Center Memorial. He won the competition to design the memorial in 2004.-Early life and education:...

.

Planning and construction

The idea of establishing a World Trade Center in New York City was first proposed in 1943. The New York State Legislature passed a bill authorizing New York Governor Thomas E. Dewey to begin developing plans for the project but the plans were put on hold in 1949. During the late 1940s and 1950s, economic growth in New York City was concentrated in Midtown Manhattan
Midtown Manhattan
Midtown Manhattan, or simply Midtown, is an area of Manhattan, New York City home to world-famous commercial zones such as Rockefeller Center, Broadway, and Times Square...

, while Lower Manhattan was left out. To help stimulate urban renewal
Urban renewal
Urban renewal is a program of land redevelopment in areas of moderate to high density urban land use. Renewal has had both successes and failures. Its modern incarnation began in the late 19th century in developed nations and experienced an intense phase in the late 1940s – under the rubric of...

, David Rockefeller
David Rockefeller
David Rockefeller, Sr. is the current patriarch of the Rockefeller family. He is the youngest and only surviving child of John D. Rockefeller, Jr. and Abby Aldrich Rockefeller, and the only surviving grandchild of oil tycoon John D. Rockefeller, founder of Standard Oil. His five siblings were...

 suggested that the Port Authority build a World Trade Center in Lower Manhattan.

Initial plans, made public in 1961, identified a site along the East River
East River
The East River is a tidal strait in New York City. It connects Upper New York Bay on its south end to Long Island Sound on its north end. It separates Long Island from the island of Manhattan and the Bronx on the North American mainland...

 for the World Trade Center. As a bi-state agency, the Port Authority required approval for new projects from the governors of both New York and New Jersey. New Jersey Governor Robert B. Meyner
Robert B. Meyner
Robert Baumle Meyner of Phillipsburg, New Jersey was an American Democratic Party politician, who served as the 44th Governor of New Jersey, from 1954 to 1962...

 objected to New York getting a $335 million project. Toward the end of 1961, negotiations with outgoing New Jersey Governor Meyner reached a stalemate.

At the time, ridership on New Jersey's Hudson and Manhattan Railroad (H&M) had declined substantially from a high of 113 million riders in 1927 to 26 million in 1958 after new automobile tunnels and bridges had opened across the Hudson River
Hudson River
The Hudson is a river that flows from north to south through eastern New York. The highest official source is at Lake Tear of the Clouds, on the slopes of Mount Marcy in the Adirondack Mountains. The river itself officially begins in Henderson Lake in Newcomb, New York...

. In a meeting between Port Authority director Austin J. Tobin
Austin J. Tobin
Austin Joseph Tobin served as the executive director of the Port of New York Authority, the precursor to the Port Authority of New York and New Jersey, from 1942 until 1972...

 and newly elected New Jersey Governor Richard J. Hughes
Richard J. Hughes
Richard Joseph Hughes was an American Democratic Party politician, who served as the 45th Governor of New Jersey from 1962 to 1970, and as Chief Justice of the New Jersey Supreme Court from 1973–1979...

, the Port Authority offered to take over the Hudson & Manhattan Railroad to have it become the Port Authority Trans-Hudson
Port Authority Trans-Hudson
PATH, derived from Port Authority Trans-Hudson, is a rapid transit railroad linking Manhattan, New York City with Newark, Harrison, Hoboken and Jersey City in metropolitan northern New Jersey...

 (PATH). The Port Authority also decided to move the World Trade Center project to the Hudson Terminal
Hudson Terminal
Hudson Terminal was an urban railway station on the Hudson and Manhattan Railroad in Lower Manhattan, New York City, and the office skyscraper built to serve the terminal.- Station :...

 building site on the west side of Lower Manhattan, a more convenient location for New Jersey commuters arriving via PATH. With the new location and Port Authority acquisition of the H&M Railroad, New Jersey, agreed to support the World Trade Center project.

Approval was also needed from New York City Mayor John Lindsay
John Lindsay
John Vliet Lindsay was an American politician, lawyer and broadcaster who was a U.S. Congressman, Mayor of New York City, candidate for U.S...

 and the New York City Council
New York City Council
The New York City Council is the lawmaking body of the City of New York. It has 51 members from 51 council districts throughout the five boroughs. The Council serves as a check against the mayor in a "strong" mayor-council government model. The council monitors performance of city agencies and...

. Disagreements with the city centered on tax issues. On , 1966, an agreement was reached that the Port Authority would make annual payments to the City in lieu of taxes for the portion of the World Trade Center leased to private tenants. In subsequent years, the payments would rise as the real estate tax
Property tax
A property tax is an ad valorem levy on the value of property that the owner is required to pay. The tax is levied by the governing authority of the jurisdiction in which the property is located; it may be paid to a national government, a federated state or a municipality...

 rate increased.

Architectural design

On September 20, 1962, the Port Authority announced the selection of Minoru Yamasaki
Minoru Yamasaki
was a Japanese-American architect, best known for his design of the twin towers of the World Trade Center, buildings 1 and 2. Yamasaki was one of the most prominent architects of the 20th century...

 as lead architect and Emery Roth & Sons
Emery Roth
Emery Roth was an American architect who designed many of the definitive New York City hotels and apartment buildings of the 1920s and 30s, incorporating Beaux-Arts and Art Deco details...

 as associate architects. Yamasaki devised the plan to incorporate twin towers; Yamasaki's original plan called for the towers to be 80 stories tall. To meet the Port Authority's requirement for 10000000 square feet (929,030.4 m²)) of office space, the buildings would each have to be 110 stories tall.

A major limiting factor in building height is the issue of elevators; the taller the building, the more elevators are needed to service the building, requiring more space-consuming elevator banks. Yamasaki and the engineers decided to use a new system with two "sky lobbies"—floors where people could switch from a large-capacity express elevator to a local elevator that goes to each floor in a section. This allowed the design to stack local elevators within the same elevator shaft. Located on the 44th and 78th floors of each tower, the sky lobbies enabled the elevators to be used efficiently, increasing the amount of usable space on each floor from 62 to 75 percent by reducing the number of elevator shafts. Altogether, the World Trade Center had 95 express and local elevators. This system was inspired by the New York City Subway
New York City Subway
The New York City Subway is a rapid transit system owned by the City of New York and leased to the New York City Transit Authority, a subsidiary agency of the Metropolitan Transportation Authority and also known as MTA New York City Transit...

 system whose lines include express stations where both express and local trains stop and local stations where only local trains stop.

Yamasaki's design for the World Trade Center, unveiled to the public on , 1964, called for a square plan approximately 208 feet (63.4 m) in dimension on each side. The buildings were designed with narrow office windows 18 inches (45.7 cm) wide, which reflected Yamasaki's fear of heights
Acrophobia
Acrophobia is an extreme or irrational fear of heights. It belongs to a category of specific phobias, called space and motion discomfort that share both similar etiology and options for treatment.Most people experience a degree of natural fear when exposed to heights, especially if there is little...

 as well as his desire to make building occupants feel secure. Yamasaki's design included building facades sheathed in aluminum-alloy. The World Trade Center was one of the most striking American implementations of the architectural ethic of Le Corbusier
Le Corbusier
Charles-Édouard Jeanneret, better known as Le Corbusier , was a Swiss-born French architect, designer, urbanist, writer and painter, famous for being one of the pioneers of what now is called modern architecture. He was born in Switzerland and became a French citizen in 1930...

 and it was the seminal expression of Yamasaki's gothic modernist tendencies.

In addition to the twin towers, the plan for the World Trade Center complex included four other low-rise buildings, which were built in the early 1970s. The 47-story 7 World Trade Center building was added in the 1980s to the north of the main complex. Altogether, the main World Trade Center complex occupied a 16 acres (64,749.8 m²) superblock.

Structural design

The structural engineering firm Worthington, Skilling, Helle & Jackson worked to implement Yamasaki's design, developing the tube-frame structural system
Tube (structure)
In structural engineering, the tube is the name given to the systems where in order to resist lateral loads a building is designed to act like a three-dimensional hollow tube, cantilevered perpendicular to the ground. The system was introduced by Fazlur Rahman Khan while at Skidmore, Owings and...

 used in the twin towers. The Port Authority's Engineering Department served as foundation engineers
Geotechnical engineering
Geotechnical engineering is the branch of civil engineering concerned with the engineering behavior of earth materials. Geotechnical engineering is important in civil engineering, but is also used by military, mining, petroleum, or any other engineering concerned with construction on or in the ground...

, Joseph R. Loring & Associates as electrical engineers
Electrical engineering
Electrical engineering is a field of engineering that generally deals with the study and application of electricity, electronics and electromagnetism. The field first became an identifiable occupation in the late nineteenth century after commercialization of the electric telegraph and electrical...

, and Jaros, Baum & Bolles as mechanical engineers
Mechanical engineering
Mechanical engineering is a discipline of engineering that applies the principles of physics and materials science for analysis, design, manufacturing, and maintenance of mechanical systems. It is the branch of engineering that involves the production and usage of heat and mechanical power for the...

. Tishman Realty & Construction Company
Tishman Realty & Construction
Tishman Realty & Construction is an American corporation that owns and operates Tishman Construction Corporation and Tishman Hotel & Realty.-Tishman Construction Corporation:...

 was the general contractor
General contractor
A general contractor is responsible for the day-to-day oversight of a construction site, management of vendors and trades, and communication of information to involved parties throughout the course of a building project.-Description:...

 on the World Trade Center project. Guy F. Tozzoli, director of the World Trade Department at the Port Authority, and Rino M. Monti, the Port Authority's Chief Engineer, oversaw the project. As an interstate agency, the Port Authority was not subject to local laws and regulations of the City of New York including building code
Building code
A building code, or building control, is a set of rules that specify the minimum acceptable level of safety for constructed objects such as buildings and nonbuilding structures. The main purpose of building codes are to protect public health, safety and general welfare as they relate to the...

s. Nonetheless, the structural engineers of the World Trade Center ended up following draft versions of the new 1968 building codes.
The tube-frame design, earlier introduced by Fazlur Khan
Fazlur Khan
Fazlur Rahman Khan was a Bangladeshi born architect and structural engineer. He is a central figure behind the "Second Chicago School" of architecture, and is regarded as the "Father of tubular design for high-rises"...

, was a new approach that allowed more open floor plans than the traditional design that distributed columns throughout the interior to support building loads. The World Trade Center towers used high-strength, load-bearing perimeter steel columns called Vierendeel trusses that were spaced closely together to form a strong, rigid wall structure, supporting virtually all lateral loads such as wind loads, and sharing the gravity load with the core columns. The perimeter structure containing 59 columns per side was constructed with extensive use of prefabricated modular pieces each consisting of three columns, three stories tall, connected by spandrel plates. The spandrel plates were welded to the columns to create the modular pieces off-site at the fabrication shop. Adjacent modules were bolted together with the splices occurring at mid-span of the columns and spandrels. The spandrel plates were located at each floor, transmitting shear stress
Shear stress
A shear stress, denoted \tau\, , is defined as the component of stress coplanar with a material cross section. Shear stress arises from the force vector component parallel to the cross section...

 between columns, allowing them to work together in resisting lateral loads. The joints between modules were staggered vertically so the column splices between adjacent modules were not at the same floor.

The core of the towers housed the elevator and utility shafts, restrooms, three stairwells, and other support spaces. The core of each tower was a rectangular area 87 by 135 feet (27 by 41 m) and contained 47 steel columns running from the bedrock to the top of the tower. The large, column-free space between the perimeter and core was bridged by prefabricated floor trusses. The floors supported their own weight as well as live loads, providing lateral stability to the exterior walls and distributing wind loads among the exterior walls. The floors consisted of 4 inches (10.2 cm) thick lightweight concrete slabs laid on a fluted steel deck. A grid of lightweight bridging trusses and main trusses supported the floors. The trusses connected to the perimeter at alternate columns and were on 6 foot 8 inch (2.03 m) centers. The top chords of the trusses were bolted to seats welded to the spandrels on the exterior side and a channel welded to the core columns on the interior side. The floors were connected to the perimeter spandrel plates with viscoelastic
Viscoelasticity
Viscoelasticity is the property of materials that exhibit both viscous and elastic characteristics when undergoing deformation. Viscous materials, like honey, resist shear flow and strain linearly with time when a stress is applied. Elastic materials strain instantaneously when stretched and just...

 dampers that helped reduce the amount of sway felt by building occupants.

Hat truss
Truss
In architecture and structural engineering, a truss is a structure comprising one or more triangular units constructed with straight members whose ends are connected at joints referred to as nodes. External forces and reactions to those forces are considered to act only at the nodes and result in...

es (or "outrigger truss") located from the 107th floor to the top of the buildings were designed to support a tall communication antenna on top of each building. Only 1 WTC (north tower) actually had an antenna fitted; it was added in 1978. The truss system consisted of six trusses along the long axis of the core and four along the short axis. This truss system allowed some load redistribution between the perimeter and core columns and supported the transmission tower.

The tube frame design using steel core and perimeter columns protected with sprayed-on fire resistant material created a relatively lightweight structure that would sway more in response to the wind compared to traditional structures such as the Empire State Building
Empire State Building
The Empire State Building is a 102-story landmark skyscraper and American cultural icon in New York City at the intersection of Fifth Avenue and West 34th Street. It has a roof height of 1,250 feet , and with its antenna spire included, it stands a total of 1,454 ft high. Its name is derived...

 that have thick, heavy masonry for fireproofing
Fireproofing
Fireproofing, a passive fire protection measure, refers to the act of making materials or structures more resistant to fire, or to those materials themselves, or the act of applying such materials. Applying a certification listed fireproofing system to certain structures allows these to have a...

 of steel structural elements. During the design process, wind tunnel
Wind tunnel
A wind tunnel is a research tool used in aerodynamic research to study the effects of air moving past solid objects.-Theory of operation:Wind tunnels were first proposed as a means of studying vehicles in free flight...

 tests were done to establish design wind pressures that the World Trade Center towers could be subjected to and structural response to those forces. Experiments also were done to evaluate how much sway occupants could comfortably tolerate, however, many subjects experienced dizziness and other ill effects. One of the chief engineers Leslie Robertson worked with Canadian engineer Alan G. Davenport
Alan Garnett Davenport
Alan Garnett Davenport was a professor at the University of Western Ontario and founder of its Boundary Layer Wind Tunnel Laboratory. He analyzed the wind's effect on a significant portion of the worlds tallest buildings including the building formerly known as the CN Tower, Sears Tower,...

 to develop viscoelastic dampers
Damping
In physics, damping is any effect that tends to reduce the amplitude of oscillations in an oscillatory system, particularly the harmonic oscillator.In mechanics, friction is one such damping effect...

 to absorb some of the sway. These viscoelastic dampers, used throughout the structures at the joints between floor trusses and perimeter columns along with some other structural modifications, reduced the building sway to an acceptable level.

Construction

In March 1965, the Port Authority began acquiring property at the World Trade Center site. Demolition work began on , 1966, to clear thirteen square blocks of low rise buildings in Radio Row
Radio Row
Radio Row is a nickname for an urban street or district specializing in the sale of radio and electronic equipment and parts. Radio Rows arose in many cities with the 1920s rise of broadcasting and declined after mid century.-New York:...

 for construction of the World Trade Center. Groundbreaking for the construction of the World Trade Center took place on , 1966.

The site of the World Trade Center was located on landfill with the bedrock
Bedrock
In stratigraphy, bedrock is the native consolidated rock underlying the surface of a terrestrial planet, usually the Earth. Above the bedrock is usually an area of broken and weathered unconsolidated rock in the basal subsoil...

 located 65 feet (19.8 m) below. To construct the World Trade Center, it was necessary to build a "bathtub
The Bathtub
"The Bathtub" refers to the underground foundation area at the site of the World Trade Center and accompanying buildings in New York City. Despite its title, it does not hold any water, rather it keeps water out and acts as a bathtub in reverse....

" with a slurry wall
Slurry wall
A slurry wall is a technique used to build reinforced-concrete walls in areas of soft earth close to open water or with a high ground water table. This technique is typically used to build diaphragm walls surrounding tunnels and open cuts, and to lay foundations.A trench is excavated to create a...

 around the West Street side of the site, to keep water from the Hudson River out. The slurry method selected by Port Authority's chief engineer, John M. Kyle, Jr., involved digging a trench, and as excavation proceeded, filling the space with a "slurry" mixture composed of bentonite
Bentonite
Bentonite is an absorbent aluminium phyllosilicate, essentially impure clay consisting mostly of montmorillonite. There are different types of bentonite, each named after the respective dominant element, such as potassium , sodium , calcium , and aluminum . Experts debate a number of nomenclatorial...

 and water, which plugged holes and kept groundwater out. When the trench was dug out, a steel cage was inserted and concrete was poured in, forcing the "slurry" out. It took fourteen months for the slurry wall to be completed; it was necessary before excavation of material from the interior of the site could begin. The 1.2 million cubic yard
Cubic yard
A cubic yard is an Imperial / U.S. customary unit of volume, used in the United States, Canada, and the UK. It is defined as the volume of a cube with sides of 1 yard in length.-Symbols:...

s (917,000 m3) of material excavated were used (along with other fill and dredge material) to expand the Manhattan shoreline across West Street to form Battery Park City.

In January 1967, the Port Authority awarded $74 million in contracts to various steel suppliers, and Karl Koch
Karl Koch Steel Consulting
Karl Koch Steel Consulting is a steel construction firm, based in Oyster Bay, New York. The company was established in the 1950s as Karl Koch Erecting Company, Inc., of Carteret, New Jersey. The Karl Koch Erecting Company was hired by the Port Authority of New York and New Jersey as one of the...

 was hired to erect the steel. Tishman Realty & Construction
Tishman Realty & Construction
Tishman Realty & Construction is an American corporation that owns and operates Tishman Construction Corporation and Tishman Hotel & Realty.-Tishman Construction Corporation:...

 was hired in to oversee construction of the project. Construction work began on the North Tower in ; construction on the South Tower was underway by . The original Hudson Tubes
Downtown Hudson Tubes
The Downtown Hudson Tubes are a pair of tunnels that carry PATH trains under the Hudson River between New York City and Jersey City in the United States. In lower Manhattan the trains travel to and from the World Trade Center station. In Jersey City the trains stop at the Exchange Place station...

, carrying PATH trains into Hudson Terminal, remained in service as elevated tunnels during the construction process until 1971 when a new PATH station
World Trade Center (PATH station)
The World Trade Center PATH station originally opened on July 19, 1909 as the Hudson Terminal. When the Hudson Terminal was torn down to make way for the World Trade Center, a new station was built, which opened in 1971...

 opened.

The topping out
Topping out
In building construction, topping out is a ceremony held when the last beam is placed at the top of a building. The term may also refer to the overall completion of the building's structure, or an intermediate point, such as when the roof is dried in...

 ceremony of 1 WTC (North Tower) took place on , 1970, while 2 WTC's ceremony (South Tower) occurred later on , 1971. The first tenants moved into the North Tower in ; the South Tower accepted tenants in . When the World Trade Center twin towers were completed, the total costs to the Port Authority had reached $900 million. The ribbon cutting ceremony was on , 1973.

Criticism

Plans to build the World Trade Center were controversial. The site for the World Trade Center was the location of Radio Row, home to hundreds of commercial and industrial tenants, property owners, small businesses, and approximately 100 residents, many of whom fiercely resisted forced relocation. A group of small businesses affected filed an injunction
Injunction
An injunction is an equitable remedy in the form of a court order that requires a party to do or refrain from doing certain acts. A party that fails to comply with an injunction faces criminal or civil penalties and may have to pay damages or accept sanctions...

 challenging the Port Authority's power of eminent domain
Eminent domain
Eminent domain , compulsory purchase , resumption/compulsory acquisition , or expropriation is an action of the state to seize a citizen's private property, expropriate property, or seize a citizen's rights in property with due monetary compensation, but without the owner's consent...

. The case made its way through the court system to the United States Supreme Court
Supreme Court of the United States
The Supreme Court of the United States is the highest court in the United States. It has ultimate appellate jurisdiction over all state and federal courts, and original jurisdiction over a small range of cases...

; the Court refused to accept the case.

Private real estate developers and members of the Real Estate Board of New York, led by Empire State Building owner Lawrence A. Wien, expressed concerns about this much "subsidized" office space going on the open market, competing with the private sector when there was already a glut of vacancies. Others questioned whether the Port Authority really ought to take on a project described by some as a "mistaken social priority".

The World Trade Center design brought criticism of its aesthetics from the American Institute of Architects
American Institute of Architects
The American Institute of Architects is a professional organization for architects in the United States. Headquartered in Washington, D.C., the AIA offers education, government advocacy, community redevelopment, and public outreach to support the architecture profession and improve its public image...

 and other groups. Lewis Mumford
Lewis Mumford
Lewis Mumford was an American historian, philosopher of technology, and influential literary critic. Particularly noted for his study of cities and urban architecture, he had a broad career as a writer...

, author of The City in History
The City in History
The City in History: Its Origins, Its Transformations, and Its Prospects is a 1961 National Book Award winner by American historian Lewis Mumford.It was first published by Harcourt, Brace & World ....

and other works on urban planning
Urban planning
Urban planning incorporates areas such as economics, design, ecology, sociology, geography, law, political science, and statistics to guide and ensure the orderly development of settlements and communities....

, criticized the project and described it and other new skyscrapers as "just glass-and-metal filing cabinets". The twin towers' narrow office windows, only 18 inches (45.7 cm) wide, were disliked by many for impairing the view from the buildings.

The trade center's "superblock", replacing a more traditional, dense neighborhood, was regarded by some critics as an inhospitable environment that disrupted the complicated traffic network typical of Manhattan. For example, in his book The Pentagon of Power, Lewis Mumford denounced the center as an "example of the purposeless giantism and technological exhibitionism that are now eviscerating the living tissue of every great city".

For many years, the immense Austin J. Tobin Plaza was often beset by brisk winds at ground level. In 1999, the outdoor plaza reopened after undergoing $12 million renovations, which involved replacing marble
Marble
Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite.Geologists use the term "marble" to refer to metamorphosed limestone; however stonemasons use the term more broadly to encompass unmetamorphosed limestone.Marble is commonly used for...

 pavers with gray and pink granite
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...

 stones, adding new benches, planters, new restaurants, food kiosks and outdoor dining areas.

North and South towers

With the construction of 7 World Trade Center in the 1980s, the World Trade Center had a total of seven buildings, but the most notable were the main two towers, each 110 stories tall, stood over 1350 feet (411.5 m) high, and occupied about one acre (43,560 square feet) of the total 16 acres (64,749.8 m²) of the site
World Trade Center site
The World Trade Center site , also known as "Ground Zero" after the September 11 attacks, sits on in Lower Manhattan in New York City...

's land. During a press conference in 1973, Yamasaki was asked, "Why two 110-story buildings? Why not one 220-story building?" His response was: "I didn't want to lose the human scale."

When completed in 1972, 1 World Trade Center (the North Tower) became the tallest building in the world for two years, surpassing the Empire State Building after a 40-year reign. The North Tower stood 1368 feet (417 m) tall and featured a telecommunications antenna or mast that was added at the top of the roof in 1978 and stood 360 feet (109.7 m) tall. With the 360 feet (109.7 m)-tall antenna/mast, the highest point of the North Tower reached 1728 ft (526.7 m). 2 World Trade Center (the South Tower) became the second tallest building in the world when completed in 1973. The South Tower's rooftop observation deck was 1362 ft (415.1 m) high and its indoor observation deck was 1310 ft (399.3 m) high. The World Trade Center towers held the height record only briefly: Chicago's Sears Tower
Sears Tower
Sears' optimistic growth projections were not met. Competition from its traditional rivals continued, with new competition by retailing giants such as Kmart, Kohl's, and Wal-Mart. The fortunes of Sears & Roebuck declined in the 1970s as the company lost market share; its management grew more...

, finished in , reached 1450 feet (442 m) at the rooftop. Throughout their existence, however, the WTC towers had more floors (at 110) than any other building. This number was not surpassed until the advent of the Burj Khalifa, which opened in 2010.

Of the 110 stories, eight were set aside for technical services in mechanical floor
Mechanical floor
A mechanical floor, mechanical penthouse, or mechanical level is a storey of a high-rise building that is dedicated to mechanical and electronics equipment. "Mechanical" is the most commonly used term, but words such as utility, technical, service, and plant are also used...

s Level B5/B6 (floors 7/8, 41/42, 75/76, and 108/109), which are four two-floor areas evenly spaced up the building. All the remaining floors were free for open-plan offices. Each floor of the towers had 40000 square feet (3,716.1 m²) of space for occupancy
Occupancy
Occupancy in building construction and building codes is the use or intended use of a building or part thereof for the shelter or support of persons, animals or property. A closely related meaning is the number of units in such a building that are rented or leased, or otherwise in-use...

. Each tower had 3800000 square feet (353,031.6 m²) of office space. Altogether the entire complex of seven buildings had 11200000 square feet (1,040,514 m²) of space.
Initially conceived as a complex dedicated to companies and organizations directly taking part in "world trade", they at first failed to attract the expected clientele. During the early years, various governmental organizations became key tenants of the World Trade Center including the State of New York
Government of New York
As in all 50 states, the head of the executive branch of the government of New York is a Governor. The legislative branch is called the Legislature and consists of a Senate and an Assembly. Unlike most states, New York electoral law permits electoral fusion; thus New York ballots tend to show a...

. It was not until the 1980s that the city's perilous financial state eased, after which an increasing number of private companies—mostly financial firms tied to Wall Street
Wall Street
Wall Street refers to the financial district of New York City, named after and centered on the eight-block-long street running from Broadway to South Street on the East River in Lower Manhattan. Over time, the term has become a metonym for the financial markets of the United States as a whole, or...

—became tenants. During the 1990s, approximately 500 companies had offices in the complex including many financial companies such as Morgan Stanley
Morgan Stanley
Morgan Stanley is a global financial services firm headquartered in New York City serving a diversified group of corporations, governments, financial institutions, and individuals. Morgan Stanley also operates in 36 countries around the world, with over 600 offices and a workforce of over 60,000....

, Aon Corporation, Salomon Brothers
Salomon Brothers
Salomon Brothers was a bulge bracket, Wall Street investment bank. Founded in 1910 by three brothers along with a clerk named Ben Levy, it remained a partnership until the early 1980s, when it was acquired by the commodity trading firm Phibro Corporation and then became Salomon Inc. Eventually...

 and the Port Authority itself. The basement concourse of the World Trade Center included The Mall at the World Trade Center
The Mall at the World Trade Center
The Mall at the World Trade Center was a shopping center located in the concourse area of the World Trade Center before it was destroyed on September 11, 2001.-Prior to 9/11:...

 along with a PATH station
World Trade Center (PATH station)
The World Trade Center PATH station originally opened on July 19, 1909 as the Hudson Terminal. When the Hudson Terminal was torn down to make way for the World Trade Center, a new station was built, which opened in 1971...

. The North Tower became the home of the corporate headquarters of Cantor Fitzgerald, and it also became the headquarters of the Port Authority of New York and New Jersey
Port Authority of New York and New Jersey
The Port Authority of New York and New Jersey is a bi-state port district, established in 1921 through an interstate compact, that runs most of the regional transportation infrastructure, including the bridges, tunnels, airports, and seaports, within the Port of New York and New Jersey...

.

Electrical service to the towers was supplied by Consolidated Edison (ConEd) at 13,800 volts. This service passed through the World Trade Center Primary Distribution Center (PDC) and sent up through the core of the building to electrical substations located on the mechanical floors. The substations "stepped" the 13,800 primary voltage down to 480/277 volt secondary power and further to 120/208 volt general power and lighting service. The complex also was served by emergency generators located in the sublevels of the towers and on the roof of 5 WTC.

The 110th floor of 1 World Trade Center (the North Tower) housed radio and television transmission equipment. The roof of 1 WTC contained a vast array of transmission antennas including the 360 ft (approx 110 m) center antenna mast, rebuilt in 1999 by Dielectric Inc. to accommodate DTV
Digital television
Digital television is the transmission of audio and video by digital signals, in contrast to the analog signals used by analog TV...

. The center mast contained the television signals for almost all NYC television broadcasters: WCBS-TV
WCBS-TV
WCBS-TV, channel 2, is the flagship station of the CBS television network, located in New York City. The station's studios are located within the CBS Broadcast Center and its transmitter is atop the Empire State Building, both in Midtown Manhattan....

 2, WNBC-TV 4, WNYW
WNYW
WNYW, virtual channel 5 , is the flagship television station of the News Corporation-owned Fox Broadcasting Company, located in New York City. The station's transmitter is atop the Empire State Building and its studio facilities are located in the Yorkville section of Manhattan...

 5, WABC-TV
WABC-TV
WABC-TV, channel 7, is the flagship station of the Disney-owned American Broadcasting Company located in New York City. The station's studios and offices are located on the Upper West Side section of Manhattan, adjacent to ABC's corporate headquarters, and its transmitter is atop the Empire State...

 7, WWOR-TV
WWOR-TV
WWOR-TV, virtual channel 9 , is the flagship station of the MyNetworkTV programming service, licensed to Secaucus, New Jersey and serving the Tri-State metropolitan area. WWOR is owned by Fox Television Stations, a division of the News Corporation, and is a sister station to Fox network flagship...

 9 Secaucus
Secaucus, New Jersey
Secaucus is a town in Hudson County, New Jersey. As of the 2010 United States Census, the town population was 16,264. Located within the New Jersey Meadowlands, it is the most suburban of the county's municipalities, though large parts of the town are dedicated to light manufacturing, retail, and...

, WPIX
WPIX
WPIX, channel 11, is a television station in New York City built, signed on, and owned by the Tribune Company. WPIX also serves as the flagship station of The CW Television Network...

 11, WNET
WNET
WNET, channel 13 is a non-commercial educational public television station licensed to Newark, New Jersey. With its signal covering the New York metropolitan area, WNET is a primary station of the Public Broadcasting Service and a primary provider of PBS programming...

 13 Newark
Newark, New Jersey
Newark is the largest city in the American state of New Jersey, and the seat of Essex County. As of the 2010 United States Census, Newark had a population of 277,140, maintaining its status as the largest municipality in New Jersey. It is the 68th largest city in the U.S...

, WPXN-TV
WPXN-TV
WPXN-TV, which broadcasts on channel 31 in New York City, is the flagship station of the Ion Television network, formerly known as Pax TV and i.-Municipal ownership:...

 31 and WNJU
WNJU
WNJU, channel 47, is the flagship station of the Spanish-language Telemundo television network, licensed to Linden, New Jersey and serving the Tri-State area television market. WNJU is owned by NBCUniversal, and is one-half of a duopoly with NBC network flagship WNBC-TV...

 47 Linden
Linden, New Jersey
- Local government :, the Mayor of Linden is . The former longtime Mayor of Linden is 82-year-old John T. Gregorio, who served as mayor of Linden for 30, nonconsecutive years and was repeatedly tagged with scandal during his mayoral career, including one felony conviction, later pardoned, which...

. It also had four NYC FM broadcasters: WPAT-FM
WPAT-FM
WPAT-FM, known on-air as "93.1 Amor", is a radio station with a Spanish-language Rhythmic AC format. Located on 93.1 FM, the station, which is licensed to Paterson, New Jersey, serves the New York City Metropolitan area.-History:...

 93.1, WNYC
WNYC
WNYC is a set of call letters shared by a pair of co-owned, non-profit, public radio stations located in New York City.WNYC broadcasts on the AM band at 820 kHz, and WNYC-FM is at 93.9 MHz. Both stations are members of National Public Radio and carry distinct, but similar news/talk programs...

 93.9, WKCR
WKCR
WKCR-FM is a radio station. Licensed to New York, New York, USA, it serves the New York area. The station is currently owned by Trustees of Columbia University in New York.-History:...

 89.9, and WKTU
WKTU
WKTU is a radio station based in New York City that plays an upbeat, gold-based CHR format. The station's broadcast transmitter is located on the top of the Empire State Building and its city of license is Lake Success, New York, with offices formerly in the "Newport" section of Jersey City, New...

 103.5. Access to the roof was controlled from the WTC Operations Control Center (OCC) located in the B1 level of 2 WTC.

Top of the World observation deck

Although most of the space in the World Trade Center complex was off-limits to the public, the South Tower featured an indoor and outdoor public observation area called Top of the World Trade Center Observatories
Top of the World Trade Center Observatories
Top of the World Trade Center Observatories was a popular tourist attraction and observation deck on the 107th floor and roof of 2 World Trade Center, the South Tower of the World Trade Center in Lower Manhattan in New York City...

 on its 107th and 110th floors. Visitors would pass through security checks added after the 1993 World Trade Center bombing, then were whisked to the 107th floor indoor observatory at a height of 1310 feet (399.3 m). The columns on each face of the building were narrowed on this level to allow 28 inches of glass between them. The Port Authority renovated the observatory in 1995, then leased it to Ogden Entertainment to operate. Attractions added to the observation deck included a simulated helicopter ride around the city. The 107th floor food court was designed with a subway car theme and featured Sbarro
Sbarro
Sbarro is a bankrupt chain of pizza restaurants that specializes in traditional Italian cuisine, including its most popular menu item "pizza by the slice." Its headquarters is located in Melville, Huntington, New York.- History :...

 and Nathan's Famous Hot Dogs. Weather permitting, visitors could take two short escalator rides up from the 107th floor viewing area to an outdoor viewing platform on the 110th floor at a height of 1377 ft (419.7 m). On a clear day, visitors could see up to 50 miles (80.5 km). An anti-suicide fence was placed on the roof itself, with the viewing platform set back and elevated above it, requiring only an ordinary railing and leaving the view unobstructed, unlike the observation deck of the Empire State Building.

Windows on the World restaurant

The North Tower had a restaurant on its 106th and 107th floors called Windows on the World
Windows on the World
Windows on the World was a complex of venues at the top floors of the North Tower of the World Trade Center in Lower Manhattan that included a restaurant, Windows on the World, a smaller restaurant called Wild Blue, and a bar called The Greatest Bar on Earth, as well as rooms for private functions...

, which opened in . The restaurant was developed by Joe Baum
Joe Baum
Joseph Harold Baum was an American restaurateur and innovator responsible for creating the country's first themed restaurants, including masterpieces such as The Four Seasons Restaurant, Windows on the World, and the restored Rainbow Room...

 at a cost of more than $17 million. Aside from the main restaurant, two offshoots were located at the top of the North Tower: "Hors d'Oeuvrerie" (offered a Danish smorgasbord during the day and sushi in the evening) and "Cellar in the Sky" (a small wine bar). Windows on the World also had a wine school program run by Kevin Zraly
Kevin Zraly
Kevin Zraly is an American wine educator and the founder of the Windows on the World Wine School, who has been described as America's most famous and entertaining wine teacher....

. Windows on the World was closed following the 1993 World Trade Center bombing. Upon reopening in 1996, Hors d'Oeuvrerie and Cellar in the Sky were replaced with the "Greatest Bar on Earth" and "Wild Blue". In 2000, its last full year of operation, Windows on the World reported revenues of $37 million, making it the highest-grossing restaurant in the United States.

Other buildings

Five smaller buildings stood around the 16 acres (64,749.8 m²) block. One was the 22-floor hotel, which opened in 1981 as the Vista Hotel, and in 1995 became the Marriott World Trade Center (3 WTC) at the southwest corner of the site. Three low-rise buildings (4 WTC, 5 WTC, and 6 WTC) in the same hollow tube design as the towers also stood around the plaza. 6 World Trade Center, at the northwest corner, housed the United States Customs Service
U.S. Customs and Border Protection
U.S. Customs and Border Protection is a federal law enforcement agency of the United States Department of Homeland Security charged with regulating and facilitating international trade, collecting import duties, and enforcing U.S. regulations, including trade, customs and immigration. CBP is the...

 and the U.S. Commodities Exchange
Commodities exchange
A commodities exchange is an exchange where various commodities and derivatives products are traded. Most commodity markets across the world trade in agricultural products and other raw materials and contracts based on them...

. 5 World Trade Center was located at the northeast corner above the PATH station
World Trade Center (PATH station)
The World Trade Center PATH station originally opened on July 19, 1909 as the Hudson Terminal. When the Hudson Terminal was torn down to make way for the World Trade Center, a new station was built, which opened in 1971...

 and 4 World Trade Center was at the southeast corner. In 1987, a 47-floor office building called 7 WTC was built north of the block. Beneath the World Trade Center complex was an underground shopping mall
The Mall at the World Trade Center
The Mall at the World Trade Center was a shopping center located in the concourse area of the World Trade Center before it was destroyed on September 11, 2001.-Prior to 9/11:...

, which in turn had connections to various mass transit facilities including the New York City Subway
New York City Subway
The New York City Subway is a rapid transit system owned by the City of New York and leased to the New York City Transit Authority, a subsidiary agency of the Metropolitan Transportation Authority and also known as MTA New York City Transit...

 system and the Port Authority's own PATH
Port Authority Trans-Hudson
PATH, derived from Port Authority Trans-Hudson, is a rapid transit railroad linking Manhattan, New York City with Newark, Harrison, Hoboken and Jersey City in metropolitan northern New Jersey...

 trains connecting Manhattan to Jersey City
Jersey City, New Jersey
Jersey City is the seat of Hudson County, New Jersey, United States.Part of the New York metropolitan area, Jersey City lies between the Hudson River and Upper New York Bay across from Lower Manhattan and the Hackensack River and Newark Bay...

, Hoboken, and Newark.

One of the world's largest gold depositories was stored underneath the World Trade Center, owned by a group of commercial banks. The 1993 bomb detonated close by the vault held. Seven weeks after the attacks, $230 million in precious metals was removed from basement vaults of 4 WTC, which included 3,800 100-Troy-ounce registered gold bars and 30,000 1,000-ounce silver bars.

Life and events

On a typical weekday 50,000 people worked in the towers with another 200,000 passing through as visitors. The complex was so large that it had its own zip code: 10048
10048 (ZIP code)
10048 is the zip code assigned to the former World Trade Center in New York City. Years after the September 11 attacks, some mail continues to be sent to 10048 by senders who have not updated their mailing lists...

. The towers offered expansive views from the observation deck atop the South Tower and the Windows on the World restaurant on top of the North Tower. The Twin Towers became known worldwide, appearing in numerous movies and television shows as well as on postcards and other merchandise, and became seen as a New York icon, in the same league as the Empire State Building, Chrysler Building
Chrysler Building
The Chrysler Building is an Art Deco style skyscraper in New York City, located on the east side of Manhattan in the Turtle Bay area at the intersection of 42nd Street and Lexington Avenue. Standing at , it was the world's tallest building for 11 months before it was surpassed by the Empire State...

 and the Statue of Liberty
Statue of Liberty
The Statue of Liberty is a colossal neoclassical sculpture on Liberty Island in New York Harbor, designed by Frédéric Bartholdi and dedicated on October 28, 1886...

.

French high wire acrobatic performer Philippe Petit
Philippe Petit
Philippe Petit is a French high-wire artist who gained fame for his high-wire walk between the Twin Towers of the World Trade Center in New York City, New York, on 7 August 1974...

 walked between the towers on a tightrope in 1974, as shown in the documentary film Man on Wire
Man on Wire
Man on Wire is a 2008 British documentary film directed by James Marsh. The film chronicles Philippe Petit's 1974 high-wire walk between the Twin Towers of New York's World Trade Center. It is based on Philippe Petit's book, To Reach the Clouds, recently released in paperback with the new title...

. Brooklyn toymaker George Willig
George Willig
George Willig is a mountain-climber from Queens, New York, United States, who climbed the South Tower of the World Trade Center on 26 May 1977, about 2½ years after tightrope walker Phillippe Petit walked between the tops of the two towers...

 scaled the south tower in 1977.

In 1983, on Memorial Day
Memorial Day
Memorial Day is a United States federal holiday observed on the last Monday of May. Formerly known as Decoration Day, it originated after the American Civil War to commemorate the fallen Union soldiers of the Civil War...

, high-rise firefighting and rescue advocate Dan Goodwin
Dan Goodwin
American Dan Goodwin is a building, rock, and sports climber, as well as a stage-four cancer survivor, originally from Kennebunkport, Maine, United States, and living as of 2010 in Lake Tahoe, California.-Building climber:...

 successfully climbed the outside of the WTC's North Tower. His stunt was meant to call attention to the inability to rescue people potentially trapped in the upper floors of skyscrapers.

The 1995 PCA world chess championship
Classical World Chess Championship 1995
The Classical World Chess Championship 1995, known at the time as the PCA World Chess Championship 1995, was held from September 10, 1995, to October 16, 1995, on the 107th floor of the former World Trade Center in New York City. Garry Kasparov, the defending champion, played Viswanathan Anand, the...

 was played on the 107th floor of the South Tower.

In January 1998, Mafia member Ralph Guarino
Ralph Guarino
Ralphie Guarino was an FBI informant and a former associate of the Decavalcante Crime Family, the New-Jersey based crime family that is sometimes considered to be the inspiration for The Sopranos...

, who had gained maintenance access to the World Trade Center, arranged a three-man crew for a heist that netted over $2 million from a Brinks delivery to the eleventh floor of the World Trade Center.

February 13, 1975 fire

On February 13, 1975, a three-alarm fire broke out on the 11th floor of the North Tower. Fire spread through the core to the 9th and 14th floors by igniting the insulation of telephone cables in a utility shaft that ran vertically between floors. Areas at the furthest extent of the fire were extinguished almost immediately and the original fire was put out in a few hours. Most of the damage was concentrated on the 11th floor, fueled by cabinets filled with paper, alcohol-based fluid for office machines, and other office equipment. Fireproofing
Fireproofing
Fireproofing, a passive fire protection measure, refers to the act of making materials or structures more resistant to fire, or to those materials themselves, or the act of applying such materials. Applying a certification listed fireproofing system to certain structures allows these to have a...

 protected the steel and there was no structural damage to the tower. Other than the damage caused by the fire, a few floors below suffered water damage from the extinguishing of the fires above. At that time, the World Trade Center had no fire sprinkler systems.

February 26, 1993 bombing

On February 26, 1993, at 12:17 p.m., a Ryder
Ryder
Ryder System, Inc. , or Ryder, is an American-based provider of transportation and supply chain management products, and is especially known for its fleet of rental trucks. Ryder specializes in fleet management, supply chain management and dedicated contracted carriage. Ryder operates in North...

 truck filled with 1500 pounds (680.4 kg) of explosives, planted by Ramzi Yousef
Ramzi Yousef
Ramzi Yousef was one of the main perpetrators of the 1993 World Trade Center bombing and a co-conspirator in the Bojinka plot. In 1995, he was arrested at a guest house in Islamabad, by the Pakistani Inter-Services Intelligence and United States Diplomatic Security Service, then extradited to the...

, detonated in the underground garage of the North Tower. The blast opened a 100 foot (30 m) hole through five sublevels with the greatest damage occurring on levels B1 and B2 and significant structural damage on level B3. Six people were killed and 50,000 other workers and visitors were left gasping for air within the 110 story towers. Many people inside the North Tower were forced to walk down darkened stairwells that contained no emergency lighting, some taking two hours or more to reach safety.

Yousef fled to Pakistan after the bombing but was arrested in Islamabad
Islamabad
Islamabad is the capital of Pakistan and the tenth largest city in the country. Located within the Islamabad Capital Territory , the population of the city has grown from 100,000 in 1951 to 1.7 million in 2011...

 in , and was extradited back to the United States to face trial. Sheikh Omar Abdel Rahman was convicted in 1996 for involvement in the bombing and other plots. Yousef and Eyad Ismoil
Eyad Ismoil
Eyad Ismoil , also transliterated as Eyad Ismail, is a Jordanian citizen who, for his role in the 1993 World Trade Center bombing, was convicted by the United States District Court for the Southern District of New York of conspiracy in 1997.-World Trade Center bombing:On February 26, 1993, Ismoil,...

 were convicted in for their carrying out the bombing. Four others had been convicted in for their involvement in the 1993 bombing. According to a presiding judge, the conspirators' chief aim at the time of the attack was to destabilize the north tower and send it crashing into the south tower, toppling both landmarks.

Following the bombing, floors that were blown out needed to be repaired to restore the structural support they provided to columns. The slurry wall was in peril following the bombing and loss of the floor slabs that provided lateral support against pressure from Hudson River water on the other side. The refrigeration plant on sublevel B5, which provided air conditioning to the entire World Trade Center complex, was heavily damaged. Subsequent to the bombing, the Port Authority installed photoluminescent markings in the stairwells. The fire alarm system
Fire alarm system
An automatic fire alarm system is designed to detect the unwanted presence of fire by monitoring environmental changes associated with combustion. In general, a fire alarm system is classified as either automatically actuated, manually actuated, or both...

 for the entire complex needed to be replaced because critical wiring and signaling in the original system was destroyed. As a memorial to the victims of the bombing of the tower, a reflecting pool
Reflecting pool
A reflecting pool or reflection pool is a water feature found in gardens, parks, and at memorial sites. It usually consists of a shallow pool of water, undisturbed by fountain jets, for a calm reflective...

 was installed with the names of those who had been killed in the blast. However, the memorial was destroyed following the attacks. Names of the victims of the 1993 bombing are included in the National September 11 Memorial & Museum.

Lease

In 1998, the Port Authority approved plans to privatize the World Trade Center. In 2001, the Port Authority sought to lease the World Trade Center to a private entity. Bids for the lease came from Vornado Realty Trust
Vornado Realty Trust
Vornado Realty Trust is a New York based real estate investment trust. It is the inheritor of real estate formerly controlled by companies including Two Guys and Alexander's.- History :...

, a joint bid between Brookfield Properties
Brookfield Properties
Brookfield Office Properties Inc. is a North American commercial real estate company. Brookfield Asset Management owns fifty percent of its outstanding common shares. The company has its headquarters operations in New York City and Toronto...

 Corporation and Boston Properties
Boston Properties
Boston Properties, Inc. is a self-managed real estate investment trust based in Boston, Massachusetts. Its primary focus is "Class A" office space which it acquires, develops, and manages in the major markets of Boston, New York City, Washington, D.C., and San Francisco...

, and a joint bid by Silverstein Properties and The Westfield Group
The Westfield Group
The Westfield Group is an Australian shopping centre group undertaking ownership, development, design, construction, funds/asset management, property management, leasing and marketing activities...

. By privatizing the World Trade Center, it would be added to the city's tax rolls and provide funds for other Port Authority projects. On , 2001, the Port Authority announced that Vornado Realty Trust had won the lease for the World Trade Center, paying $3.25 billion for the 99-year lease. Vornado
Vornado Realty Trust
Vornado Realty Trust is a New York based real estate investment trust. It is the inheritor of real estate formerly controlled by companies including Two Guys and Alexander's.- History :...

 outbid Silverstein by $600 million though Silverstein upped his offer to $3.22 billion. However, Vornado insisted on last minute changes to the deal, including a shorter 39-year lease, which the Port Authority considered nonnegotiable. Vornado later withdrew and Silverstein's bid for the lease to the World Trade Center was accepted on , 2001, and closed on , 2001.

Destruction

On September 11, 2001, terrorists hijacked American Airlines Flight 11
American Airlines Flight 11
American Airlines Flight 11 was American Airlines' daily scheduled morning transcontinental flight from Logan International Airport, in Boston, Massachusetts, to Los Angeles International Airport, in Los Angeles, California...

 and crashed it into the northern facade of the north tower at 08:46 a.m., the aircraft striking between the 93rd and 99th floors. Seventeen minutes later, at 9:03 a.m., a second team of terrorists crashed the similarly hijacked United Airlines Flight 175
United Airlines Flight 175
United Airlines Flight 175 was United Airlines' daily scheduled morning transcontinental flight, from Logan International Airport in Boston, Massachusetts, to Los Angeles International Airport in Los Angeles, California...

 into the south tower, striking it between the 77th and 85th floors. The damage caused to the north tower by Flight 11 destroyed any means of escape from above the impact zone, trapping 1,344 people. Flight 175 had a much more off-centered impact compared to Flight 11, and a single stairwell was left intact; however, only a few people managed to pass through it successfully before the tower collapsed. Although the south tower was struck lower than the north tower, thus affecting more floors, a smaller number, fewer than 700, were killed instantly or trapped. At 9:59 a.m., the South Tower collapsed
Collapse of the World Trade Center
The twin towers of the World Trade Center collapsed on September 11, 2001, as a result of al-Qaeda's September 11 attacks, in which terrorists affiliated with al-Qaeda hijacked four commercial passenger jet airliners, flying one into the North Tower and another into the South Tower...

 after burning for approximately 56 minutes. The fire caused steel structural elements, already weakened from the plane impact, to fail. The north tower collapsed at 10:28 a.m., after burning for approximately 102 minutes.

At 5:20 p.m. on , 2001, 7 World Trade Center
7 World Trade Center
7 World Trade Center is a building in New York City located across from the World Trade Center site in Lower Manhattan. It is the second building to bear that name and address in that location. The original structure was completed in 1987 and was destroyed in the September 11 attacks...

 started to collapse with the crumble of the east penthouse, and it collapsed completely at 5:21 p.m. owing to uncontrolled fires causing structural failure. 3 World Trade Center, a Marriott hotel, was destroyed during the collapse of the two towers. The three remaining buildings in the WTC plaza sustained heavy damage from debris and were ultimately demolished. The Deutsche Bank Building
Deutsche Bank Building
The Deutsche Bank Building was a skyscraper at 130 Liberty Street in New York City, United States, adjacent to the World Trade Center . Opened in 1974 as Bankers Trust Plaza, the building was acquired by Deutsche Bank when it acquired Bankers Trust in 1998. It was part of the skyline of Lower...

 across Liberty Street
Liberty Street (Manhattan)
Liberty Street is a street in New York City that stretches east-west from the middle of Lower Manhattan almost to the East River. It borders such sites as One Chase Manhattan Plaza, the Federal Reserve Bank of New York, One Liberty Plaza, Liberty Plaza Park, the World Trade Center site, the World...

 from the World Trade Center complex was later condemned owing to the uninhabitable toxic conditions inside; it was deconstructed, with work completed in early 2011. The Borough of Manhattan Community College
Borough of Manhattan Community College
The Borough of Manhattan Community College is one of six two-year colleges within the City University of New York system and the only one in Manhattan. Founded in 1963, BMCC originally offered business-oriented and liberal arts degrees for those intending to enter the business world or transfer...

's Fiterman Hall at 30 West Broadway
West Broadway (Manhattan)
West Broadway, not to be confused with Broadway, is a north-south street in the New York City borough of Manhattan separated into two parts by a park. The northern part begins at TriBeCa Park, near the intersection of Sixth Avenue, Walker Street and Beach Street in TriBeCa...

 was also condemned owing to extensive damage in the attacks and is slated for deconstruction
Deconstruction (building)
In the context of physical construction, deconstruction is the selective dismantlement of building components, specifically for re-use, recycling, and waste management. It differs from demolition where a site is cleared of its building by the most expedient means. Deconstruction has also been...

.

In the immediate aftermath of the attacks, media reports suggested that tens of thousands might have been killed in the attacks, as on any given day over 50,000 people could be inside the towers. Ultimately, 2,753 death certificates (excluding those for hijackers) were filed relating to the 9/11 attacks, including one filed for Felicia Dunn-Jones, who was added to the official death toll in ; Dunn-Jones died five months later from a lung condition linked to exposure to dust during the collapse of the World Trade Center. Three other victims were then added to the official death toll by the city medical examiner's office: Dr. Sneha Anne Philip
Sneha Anne Philip
Sneha Anne Philip was an Indian American physician who was last seen on September 10, 2001 by a department store surveillance camera near her Lower Manhattan apartment. She may have returned to the building at some point that night or the next morning...

, who was last seen the day before the attacks; Leon Heyward, a man who developed lymphoma and subsequently died in 2008 as a result of dust ingestion during the events following the attacks to the Twin Towers; and Jerry Borg, who died in December 2010 of pulmonary sarcoidosis determined in June 2011 to be the result of dust from the attacks. Cantor Fitzgerald L.P., an investment bank on the 101st–105th floors of One World Trade Center, lost 658 employees, considerably more than any other employer, while Marsh & McLennan Companies
Marsh & McLennan Companies
Marsh & McLennan Companies, Inc. is a US-based global professional services and insurance brokerage firm. In 2007, it had over 57,000 employees and annual revenues of $10.49 billion. Marsh & McLennan Companies was ranked the 221st largest corporation in the United States by the 2009 Fortune 500...

, located immediately below Cantor Fitzgerald on floors 93–101 (the location of Flight 11's impact), lost 295 employees, and 175 employees of Aon Corporation were killed. In addition, 343 of the dead were New York City firefighters
New York City Fire Department
The New York City Fire Department or the Fire Department of the City of New York has the responsibility for protecting the citizens and property of New York City's five boroughs from fires and fire hazards, providing emergency medical services, technical rescue as well as providing first response...

, 84 were Port Authority employees, of whom 37 were members of the Port Authority Police Department
Port Authority Police Department
The Port Authority of New York and New Jersey Police Department, or Port Authority Police Department , is a law enforcement agency in New York and New Jersey, the duties of which are to protect all facilities owned by the Port Authority of New York and New Jersey, and to enforce state and city laws...

, and another 23 were New York City Police Department
New York City Police Department
The New York City Police Department , established in 1845, is currently the largest municipal police force in the United States, with primary responsibilities in law enforcement and investigation within the five boroughs of New York City...

 officers. Ten years after the attacks, only 1,629 victims have been positively identified. Of all the people who were still in the towers when they collapsed, only 20 were pulled out alive. PAPD Officers William Jimeno and Sgt. John McLoughlin were survivors 18 and 19.

Rebuilding

After years of delay and controversy, reconstruction at the World Trade Center site
World Trade Center site
The World Trade Center site , also known as "Ground Zero" after the September 11 attacks, sits on in Lower Manhattan in New York City...

 is now well underway. Both One and Four World Trade Center
Four World Trade Center
Four World Trade Center is a skyscraper under construction as part of the new World Trade Center in New York City at 150 Greenwich Street on the east side of Greenwich Street, across from the original location of the Twin Towers that were destroyed during the September 11 attacks...

 are on track for completion and occupancy by 2013. The 9/11 memorial is complete, with the museum set to open in 2012. Two
Two World Trade Center
Two World Trade Center is an 88-story skyscraper under construction as part of the new World Trade Center complex in Lower Manhattan of New York City. The tower will be located in the northeast corner of the World Trade Center site, where the former 5 World Trade Center stood, with the original 2...

 and Three World Trade Center
Three World Trade Center
Three World Trade Center is a skyscraper to become part of the World Trade Center reconstruction in New York City. The office building will be on the east side of Greenwich Street, across the street from the original location of the Twin Towers that were destroyed during the September 11 attacks...

, as well as the Transportation Hub
World Trade Center (PATH station)
The World Trade Center PATH station originally opened on July 19, 1909 as the Hudson Terminal. When the Hudson Terminal was torn down to make way for the World Trade Center, a new station was built, which opened in 1971...

, are also making progress, set to be finished before 2015.

History

The process of cleanup and recovery continued 24 hours a day over a period of eight months. Debris was transported from the World Trade Center site to Fresh Kills
Fresh Kills
Fresh Kills is a stream and freshwater estuary in the western portion of the New York City borough of Staten Island...

 on Staten Island
Staten Island
Staten Island is a borough of New York City, New York, United States, located in the southwest part of the city. Staten Island is separated from New Jersey by the Arthur Kill and the Kill Van Kull, and from the rest of New York by New York Bay...

, where it was further sifted. On , 2002, a ceremony was held to officially mark the end of the cleanup efforts. In 2002, ground was broken on construction of a new 7WTC building located just to the north of the main World Trade Center site. Since it was not part of the site master plan, Larry Silverstein was able to proceed without delay on the rebuilding of 7 World Trade Center, which was completed and officially opened in ; this had been considered a priority since restoring the Consolidated Edison Cos. electrical substation in the building's lower floors was necessary to meet power demands of Lower Manhattan. While 7 World Trade Center was not part of the master plan for the Twin Towers site, Silverstein and Con Edison recognized that the rebuilding of 7 World Trade Center would have to be consistent with the master plan which was expected to re-open the street grid which had been blocked by the original World Trade Center super-block. As a result, the design for the new 7 World Trade Center allowed for the re-opening of Greenwich Street, which had been blocked by the original 7 World Trade Center. A temporary PATH station
World Trade Center (PATH station)
The World Trade Center PATH station originally opened on July 19, 1909 as the Hudson Terminal. When the Hudson Terminal was torn down to make way for the World Trade Center, a new station was built, which opened in 1971...

 at the World Trade Center opened in ; it will be replaced by a permanent station designed by Santiago Calatrava
Santiago Calatrava
Santiago Calatrava Valls is a Spanish architect, sculptor and structural engineer whose principal office is in Zürich, Switzerland. Classed now among the elite designers of the world, he has offices in Zürich, Paris, Valencia, and New York City....

.

With the main World Trade Center site, numerous stakeholders were involved including Silverstein and the Port Authority, which in turn meant the Governor of New York State, George Pataki
George Pataki
George Elmer Pataki is an American politician who was the 53rd Governor of New York. A member of the Republican Party, Pataki served three consecutive four-year terms from January 1, 1995 until December 31, 2006.- Early life :...

, had some authority. In addition, the victims' families, people in the surrounding neighborhoods, Mayor Michael Bloomberg
Michael Bloomberg
Michael Rubens Bloomberg is the current Mayor of New York City. With a net worth of $19.5 billion in 2011, he is also the 12th-richest person in the United States...

, and others wanted input. Governor Pataki established the Lower Manhattan Development Corporation
Lower Manhattan Development Corporation
The Lower Manhattan Development Corporation was formed in July 2002, after the September 11 attacks to plan the reconstruction of Lower Manhattan and distribute nearly $10 billion in federal funds aimed at rebuilding downtown Manhattan....

 (LMDC) in as an official commission to oversee the rebuilding process. The LMDC held a competition to solicit possible designs for the site. The Memory Foundations
Memory Foundations
Memory Foundations is the name given by Daniel Libeskind to his site plan for the World Trade Center, which was selected by the Lower Manhattan Development Corporation to be the master plan for rebuilding at the World Trade Center site in New York City....

 design by Daniel Libeskind
Daniel Libeskind
Daniel Libeskind, is an American architect, artist, and set designer of Polish-Jewish descent. Libeskind founded Studio Daniel Libeskind in 1989 with his wife, Nina, and is its principal design architect...

 was chosen as the master plan for the World Trade Center site. The plan included the 1776 feet (541.3 m) Freedom Tower (now known as One World Trade Center) as well as a memorial and a number of other office towers. Out of the World Trade Center Site Memorial Competition
World Trade Center Site Memorial Competition
The World Trade Center Site Memorial Competition was an open, international memorial contest, initiated by the Lower Manhattan Development Corporation , as per the specifications of architect Daniel Libeskind, to design a World Trade Center Site Memorial on a portion of the World Trade Center site...

, a design by Michael Arad
Michael Arad
Michael Arad is an Israeli-American architect who best known for being the designer of the World Trade Center Memorial. He won the competition to design the memorial in 2004.-Early life and education:...

 and Peter Walker entitled Reflecting Absence was selected in .

On March 13, 2006, workers arrived at the World Trade Center site to remove remaining debris and start surveying work. This marked the official start of construction of the National September 11 Memorial & Museum, though not without controversy and concerns from some family members. In , the Port Authority and Larry Silverstein reached an agreement in which Silverstein ceded rights to develop the Freedom Tower and Tower Five in exchange for financing with Liberty Bonds for Towers Two, Three, and Four. On , 2006, a ground-breaking ceremony was held for the Freedom Tower.

In May 2006, architects Richard Rogers
Richard Rogers
Richard George Rogers, Baron Rogers of Riverside CH Kt FRIBA FCSD is a British architect noted for his modernist and functionalist designs....

 and Fumihiko Maki
Fumihiko Maki
is a Japanese architect and currently teaching at Keio University SFC.- Biography :After studying at the University of Tokyo he moved to the Cranbrook Academy of Art in Bloomfield Hills, Michigan, and then to Harvard Graduate School of Design. In 1956, he took a post as assistant professor of...

 were announced as the architects for Towers Three and Four, respectively. The final designs for Towers Two, Three and Four were unveiled on , 2006. Tower Two, or 200 Greenwich Street, will have a roof height of 1254 feet (382.2 m) and a 96 feet (29.3 m) tripod spire for a total of 1350 feet (411.5 m). Tower Three, or 175 Greenwich Street will have a roof height of 1,155 feet (352 m) and an antenna height reaching 1255 feet (382.5 m). Tower Four, or 150 Greenwich Street, will have an overall height of 946 feet (288.3 m). On , 2007, the Port Authority of New York and New Jersey announced that JP Morgan Chase will build Tower 5, a 42-story building on Site 5 currently occupied by the Deutsche Bank Building, and Kohn Pedersen Fox
Kohn Pedersen Fox
Kohn Pedersen Fox Associates , an architectural firm responsible for several world-renowned buildings, provides architectural, interior and urban design as well as programming and master planning services for clients in both the public and private sectors...

 was selected as the architect for the building. Four renowned architects, including Spanish architect Santiago Calatrava
Santiago Calatrava
Santiago Calatrava Valls is a Spanish architect, sculptor and structural engineer whose principal office is in Zürich, Switzerland. Classed now among the elite designers of the world, he has offices in Zürich, Paris, Valencia, and New York City....

, who designed the transit hub, One WTC designer David Childs
David Childs
David M. Childs is the Consulting Design Partner at Skidmore, Owings and Merrill. He is best known for his redesign of the new One World Trade Center in New York....

 of Skidmore, Owings and Merrill
Skidmore, Owings and Merrill
Skidmore, Owings and Merrill LLP is an American architectural and engineering firm that was formed in Chicago in 1936 by Louis Skidmore and Nathaniel Owings; in 1939 they were joined by John O. Merrill. They opened their first branch in New York City, New York in 1937. SOM is one of the largest...

, and the famed British architect Norman Foster of Foster and Partners
Foster and Partners
Foster + Partners is an architectural firm based in London. The practice is led by its founder and Chairman, Norman Foster, and has constructed many high-profile glass-and-steel buildings....

 designed Tower Two and masterminded the iconic diamond design, will greatly enhance the street-level atmosphere of the rebuilt site. The projects will be complete between early 2013 to mid 2014.

As of August 2011, One World Trade Center is at 80 stories with glass up to the 54th floor, Tower Four is up around 38 stories with glass up to the 15th floor, and the former Deutsche Bank Building
Deutsche Bank Building
The Deutsche Bank Building was a skyscraper at 130 Liberty Street in New York City, United States, adjacent to the World Trade Center . Opened in 1974 as Bankers Trust Plaza, the building was acquired by Deutsche Bank when it acquired Bankers Trust in 1998. It was part of the skyline of Lower...

 has been completely dismantled and the Port Authority is working on their Vehicle Security Center. The World Trade Center Transportation Hub's PATH hall is nearly complete. The memorial officially opened to relatives of the deceased on September 11, 2011, and to the general public on September 12. World Trade Center Tower Three and Two's foundations are becoming visible, and Tower Three will be completed in mid 2014 if Silverstein Properties can meet requirements set by the Port Authority, as they very likely will. Tower Two will also be completed on schedule according to the construction company. However construction will be complete on Tower Two on time, given that numerous American and Chinese companies are "very interested" in leasing space at the WTC. Publishing Giant Conde Nast
Condé Nast Publications
Condé Nast, a division of Advance Publications, is a magazine publisher. In the U.S., it produces 18 consumer magazines, including Architectural Digest, Bon Appétit, GQ, The New Yorker, Vanity Fair, and Vogue, as well as four business-to-business publications, 27 websites, and more than 50 apps...

 has agreed to move its headquarters to One World Trade Center, and with this shift many more are expected to follow.

Controversy and criticism

There was much debate regarding the future of Ground Zero
World Trade Center site
The World Trade Center site , also known as "Ground Zero" after the September 11 attacks, sits on in Lower Manhattan in New York City...

 following the destruction of the World Trade Center. Disagreement and controversy regarding who owned the property and what would be built there hindered construction at the site for several years. Many wanted the Twin Towers to be rebuilt, but stronger and taller. This movement was led by an informal organization called the Twin Towers Alliance. Others, considering the area sacred, did not want anything built there at all or wanted the entire site to become a memorial. Finally, a master plan was agreed upon, which would feature a memorial and museum where the original twin towers stood and six new skyscrapers surrounding it.

One World Trade Center itself has been met with criticism. The original design, which was asymmetrical, significantly shorter, and called for an off-center spire, was met with much disapproval, causing a new one to be devised. A key feature of the final design, the fortified, windowless base, was also denounced as looking dreary and unwelcoming. To alleviate this problem, the designers decided to clad it with prismatic glass panels. Since the failure of that plan, it is now unclear what the base will be covered with. The name change from Freedom Tower to One World Trade Center was met with some criticism. Governor of New York George Pataki stated in 2003 that, "The Freedom Tower isn't going to be One World Trade Center, it's going to be the Freedom Tower."

WTC American flags

A small number of American flags
Flag of the United States
The national flag of the United States of America consists of thirteen equal horizontal stripes of red alternating with white, with a blue rectangle in the canton bearing fifty small, white, five-pointed stars arranged in nine offset horizontal rows of six stars alternating with rows...

 which flew on or near the WTC during the attacks were recovered during the clean-up efforts. One was found at 5:30 a.m. on the morning of , 2001, by New York City Police Sergeant Gerald Kane and Detective Peter Friscia. While assisting rescue teams at "Ground Zero
Ground zero
The term ground zero describes the point on the Earth's surface closest to a detonation...

", they noticed that the large American flag that once flew in front of the WTC at Church Street had been blown off the flagpole during the collapse of the buildings and was tangled upside down on a streetlight several feet away. The two men recruited a number of soldiers and firefighters in the area who hoisted a ladder to the top of the streetlight. Detective Friscia climbed the rungs of the ladder to the top, untangled and retrieved the flag and brought it down to the ground. Kerik later released the flag to NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

 officials and it was transported aboard the space shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...

 Endeavour
Space Shuttle Endeavour
Space Shuttle Endeavour is one of the retired orbiters of the Space Shuttle program of NASA, the space agency of the United States. Endeavour was the fifth and final spaceworthy NASA space shuttle to be built, constructed as a replacement for Challenger...

 (STS-108
STS-108
STS-108 was a Space Shuttle mission to the International Space Station flown by Space Shuttle Endeavour. Its primary objective was to deliver supplies to and help maintain the ISS....

) as part of its –17, 2001, mission to the International Space Station. On Flag Day
Flag Day
A flag day is a flag-related holiday—either a day designated for flying a certain flag , or a day set aside to celebrate a historical event such as a nation's adoption of its flag....

, , 2002, the American flag was returned to the people of New York City by Sean O'Keefe of NASA and Commander Dom Gorie and the crew members of the Endeavour, in a ceremony at the Rose Center at the American Museum of Natural History
American Museum of Natural History
The American Museum of Natural History , located on the Upper West Side of Manhattan in New York City, United States, is one of the largest and most celebrated museums in the world...

. The flag is secured and maintained by New York City's Commissioner of Records and is part of the annual 9/11 ceremony at Ground Zero.
Another flag, which had originally flown atop one of the towers, was recovered three days after the attacks and, owing to its poor condition, was turned over to the National Guard for its ceremonial destruction. The National Guard then discovered from a label that the flag was the property of the Port Authority, and instead of retiring the flag, returned it. It was then used during the memorial service of several first responders, and was flown during both the 2001 World Series
2001 World Series
-Game 1:Saturday, October 27, 2001 at Bank One Ballpark in Phoenix, ArizonaArizona showed no fear and chased Yankees starter Mike Mussina after just three innings. The Yankees gave up five unearned runs and the Diamondbacks rode Curt Schilling's seven strong innings to a 9–1 rout...

 and Super Bowl XXXVI
Super Bowl XXXVI
Super Bowl XXXVI was an American football game played on February 3, 2002 at the Louisiana Superdome in New Orleans, Louisiana to decide the National Football League champion following the 2001 regular season. The American Football Conference champion New England Patriots won their first Super...

. The flag was also used, controversially, in the Opening Ceremony of the 2002 Winter Olympics
2002 Winter Olympics
The 2002 Winter Olympics, officially the XIX Olympic Winter Games, were a winter multi-sport event that was celebrated in February 2002 in and around Salt Lake City, Utah, United States. Approximately 2,400 athletes from 77 nations participated in 78 events in fifteen disciplines, held throughout...

 held in Salt Lake City. Initially the International Olympic Committee
International Olympic Committee
The International Olympic Committee is an international corporation based in Lausanne, Switzerland, created by Pierre de Coubertin on 23 June 1894 with Demetrios Vikelas as its first president...

 (IOC) refused to allow the flag to be used in ceremony, fearing it would be seen as too pro-American, overly patriotic, and create complications during future ceremonies. But an agreement was eventually reached between the event organizers and the IOC, which allowed the flag to be carried into Rice-Eccles Olympic Stadium by both U.S. athletes and 9/11 first responders. The flag was carried into the stadium in silence, after which the flag bearers paused in front of the Mormon Tabernacle Choir
Mormon Tabernacle Choir
The Mormon Tabernacle Choir, sometimes colloquially referred to as MoTab, is a Grammy and Emmy Award winning, 360-member, all-volunteer choir. The choir is part of The Church of Jesus Christ of Latter-day Saints . However, the choir is completely self-funded, traveling and producing albums to...

, allowing them to sing The Star-Spangled Banner
The Star-Spangled Banner
"The Star-Spangled Banner" is the national anthem of the United States of America. The lyrics come from "Defence of Fort McHenry", a poem written in 1814 by the 35-year-old lawyer and amateur poet, Francis Scott Key, after witnessing the bombardment of Fort McHenry by the British Royal Navy ships...

, while a separate American flag was raised.

A number of flags from other countries were also recovered from the World Trade Center site. A New Zealand flag was presented to the then Prime Minister of New Zealand
Prime Minister of New Zealand
The Prime Minister of New Zealand is New Zealand's head of government consequent on being the leader of the party or coalition with majority support in the Parliament of New Zealand...

, Helen Clark
Helen Clark
Helen Elizabeth Clark, ONZ is a New Zealand political figure who was the 37th Prime Minister of New Zealand for three consecutive terms from 1999 to 2008...

, by representatives of the New York City Fire Department. Two of the casualties were New Zealanders. Conservators mounted and framed the flag and it now hangs in the main stairwell of Parliament House, the main building of the New Zealand Parliament Complex
New Zealand Parliament Buildings
The New Zealand Parliament Buildings house the New Zealand Parliament and are on a 45,000 square metre site at the northern end of Lambton Quay, Wellington...

. A Union flag
Union Flag
The Union Flag, also known as the Union Jack, is the flag of the United Kingdom. It retains an official or semi-official status in some Commonwealth Realms; for example, it is known as the Royal Union Flag in Canada. It is also used as an official flag in some of the smaller British overseas...

 of the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 was also recovered, and is now housed at the Imperial War Museum North
Imperial War Museum North
Imperial War Museum North is a museum in the Metropolitan Borough of Trafford in Greater Manchester, England. One of the five branches of the Imperial War Museum, the museum explores the impact of modern conflicts on people and society. It is the first branch of the Imperial War Museum to be...

 in Manchester
Manchester
Manchester is a city and metropolitan borough in Greater Manchester, England. According to the Office for National Statistics, the 2010 mid-year population estimate for Manchester was 498,800. Manchester lies within one of the UK's largest metropolitan areas, the metropolitan county of Greater...

, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

. The United Kingdom suffered the most casualties after the United States, with around 60 to 70 Britons killed during the attacks.

In popular culture

The World Trade Center was an iconic structure and has been featured in numerous films as well as appearing in many television shows, cartoons, comic books, video games and music videos.

See also

  • Project Rebirth
    Project Rebirth
    Project Rebirth, Inc. is a U.S. 501 non-profit organization created to support victims and early responders to catastrophic events through documentary footage recording the rebuilding at the site of World Trade Center following the September 11 attacks and seven years in the lives of people...

  • The Sphere
    The Sphere
    The Sphere is a large metallic sculpture by German sculptor Fritz Koenig, currently displayed in Battery Park, New York City, that once stood in the middle of Austin J. Tobin Plaza, the area between the World Trade Center towers in Manhattan...

  • The Philippe Petit High Wire Walk Between the Towers

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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