This article is about a structural feature. For the expression concerning limitations on advancement, see glass ceiling

Glass ceiling

In economics, the term glass ceiling refers to "the unseen, yet unbreachable barrier that keeps minorities and women from rising to the upper rungs of the corporate ladder, regardless of their qualifications or achievements." Initially, the metaphor applied to barriers in the careers of women but...

. For the 2004 Maritime album, see Glass Floor

Glass Floor

Glass Floor was the debut full length album by the indie pop group, Maritime. It was the follow-up to Adios EP, which contained five tracks...

.

A glass floor is a transparent section of a floor

Floor

A floor is the walking surface of a room or vehicle. Floors vary from simple dirt in a cave to many-layered surfaces using modern technology...

, found most often in building

Building

In architecture, construction, engineering, real estate development and technology the word building may refer to one of the following:...

s (usually in the observation decks of tower

Tower

A tower is a tall structure, usually taller than it is wide, often by a significant margin. Towers are distinguished from masts by their lack of guy-wires....

s) or boat

Boat

A boat is a watercraft of any size designed to float or plane, to provide passage across water. Usually this water will be inland or in protected coastal areas. However, boats such as the whaleboat were designed to be operated from a ship in an offshore environment. In naval terms, a boat is a...

s in order to facilitate viewing directly beneath where one is standing.

Usually made of a reinforced glass

Glass

Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...

, the most common use is as a tourist attraction

Tourism

Tourism is travel for recreational, leisure or business purposes. The World Tourism Organization defines tourists as people "traveling to and staying in places outside their usual environment for not more than one consecutive year for leisure, business and other purposes".Tourism has become a...

. Glass-bottom boats are popular for allowing a better view into the water

Body of water

A body of water or waterbody is any significant accumulation of water, usually covering the Earth or another planet. The term body of water most often refers to large accumulations of water, such as oceans, seas, and lakes, but it may also include smaller pools of water such as ponds, puddles or...

. Glass as a flooring material is used in both residential and commercial structures. Special hollow glass blocks known as glass paver

Paver

Paver may refer to:* Paver , a multi-shaped, multi-colored piece of concrete* Paver , an engineering vehicle* Michelle Paver , British writer...

s are often used in combination with a metal

Metal

A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...

 frame

Space frame

A space frame or space structure is a truss-like, lightweight rigid structure constructed from interlocking struts in a geometric pattern. Space frames can be used to span large areas with few interior supports...

.

At 4000 feet (1219 m), the highest glass floor above ground is the novel outdoor application of the Grand Canyon Skywalk

Grand Canyon Skywalk

The Grand Canyon Skywalk is a transparent horseshoe-shaped cantilever bridge and tourist attraction in Arizona near the Colorado River on the edge of a side canyon in the Grand Canyon West area of the main canyon...

, operated by the Hualapai

Hualapai

The Hualapai or Walapai are a tribe of Native Americans who live in the mountains of northwestern Arizona, United States. The name is derived from "hwa:l," the Hualapai word for ponderosa pine, "Hualapai" meaning "people of the ponderosa pine"...

 Indian tribe. The highest above ground level in a freestanding structure is in the CN Tower

CN Tower

The CN Tower is a communications and observation tower in Downtown Toronto, Ontario, Canada. Standing tall, it was completed in 1976, becoming the world's tallest free-standing structure and world's tallest tower at the time. It held both records for 34 years until the completion of the Burj...

 in Toronto

Toronto

Toronto is the provincial capital of Ontario and the largest city in Canada. It is located in Southern Ontario on the northwestern shore of Lake Ontario. A relatively modern city, Toronto's history dates back to the late-18th century, when its land was first purchased by the British monarchy from...

, Ontario

Ontario

Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....

at 1122 feet (342 m).