Underground living refers simply to living below the ground's surface, whether in naturally occurring cave

Cave

A cave or cavern is a natural underground space large enough for a human to enter. The term applies to natural cavities some part of which is in total darkness. The word cave also includes smaller spaces like rock shelters, sea caves, and grottos.Speleology is the science of exploration and study...

s or in built structures.

Underground homes are an attractive alternative to traditionally built homes for some house seekers, especially those who are looking to minimize their home's negative impact on the environment

Green home

A Green home is a type of house useless area is designed to be environmentally friendly and sustainable, focusing on the efficient use of "energy, water, and building materials."-Components:...

. Besides the novelty of living underground, some of the advantages of underground houses include resistance to severe weather, an exceptionally quiet living space, an unobtrusive presence in the surrounding landscape, and a nearly constant interior temperature due to the natural insulating properties of the surrounding earth. The greatest draw for most, however, is the energy efficiency

Efficient energy use

Efficient energy use, sometimes simply called energy efficiency, is the goal of efforts to reduce the amount of energy required to provide products and services. For example, insulating a home allows a building to use less heating and cooling energy to achieve and maintain a comfortable temperature...

 and environmental friendliness

Environmentally friendly

Environmentally friendly are terms used to refer to goods and services, laws, guidelines and policies claimed to inflict minimal or no harm on the environment....

 of such houses. Because of the stable subsurface temperature of the Earth

Earth

Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

, heating and cooling costs are often much lower in an underground house than in a comparable above-ground house. When combined with solar design, it is possible to eliminate energy bills entirely. Initial building costs are also often exceptionally low, as underground building is largely subtractive rather than additive, and because the natural materials

Soil

Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...

 displaced by the construction can be recycled as building materials. However, underground living does have certain disadvantages, such as the potential for flooding, which in some cases may require special pumping systems to be installed.

Underground living has been a feature of fiction, such as the hobbit holes of the Shire as described in the stories of J. R. R. Tolkien

J. R. R. Tolkien

John Ronald Reuel Tolkien, CBE was an English writer, poet, philologist, and university professor, best known as the author of the classic high fantasy works The Hobbit, The Lord of the Rings, and The Silmarillion.Tolkien was Rawlinson and Bosworth Professor of Anglo-Saxon at Pembroke College,...

 and The Underground City by Jules Verne

Jules Verne

Jules Gabriel Verne was a French author who pioneered the science fiction genre. He is best known for his novels Twenty Thousand Leagues Under the Sea , A Journey to the Center of the Earth , and Around the World in Eighty Days...

. It is also the preferred mode of housing to communities in such extreme environments as Australia's

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 Coober Pedy

Coober Pedy, South Australia

Coober Pedy is a town in northern South Australia, 846 kilometres north of Adelaide on the Stuart Highway. According to the 2006 census, its population was 1,916 . The town is sometimes referred to as the "opal capital of the world" because of the quantity of precious opals that are mined there...

, Berber

Berber people

Berbers are the indigenous peoples of North Africa west of the Nile Valley. They are continuously distributed from the Atlantic to the Siwa oasis, in Egypt, and from the Mediterranean to the Niger River. Historically they spoke the Berber language or varieties of it, which together form a branch...

 caves as those in Matmâta, Tunisia, and even Amundsen-Scott South Pole Station

Amundsen-Scott South Pole Station

The Amundsen–Scott South Pole Station is the American scientific research station on the high plateau of Antarctica. This station is located at the southernmost place on the Earth, the Geographic South Pole, at an elevation of 2,835 meters above sea level.The original Amundsen-Scott Station was...

. Underground living is even being considered for the design of a future base on Mars

Caves of Mars Project

The Caves of Mars Project was a program funded through Phase II by the NASA Institute for Advanced Conceptsto assess the best place to situate the research and habitation modules that a manned mission to Mars would require....

. Completely underground homes need not be considered impractical or unaesthetic any longer. With today's technologies one can direct natural light into living spaces with light tubes

Light tube

Light tubes or light pipes are used for transporting or distributing natural or artificial light. In their application to daylighting, they are also often called sun pipes, sun scopes, solar light pipes, sky lights or daylight pipes.Generally speaking, a light pipe or light tube may refer to:* a...

. Virtual windows can provide any view one chooses by the use of cameras or internet cam feeds. Even whole walls can display whatever view one wants someday soon (wall-sized flat screen monitors are still too expensive to be widely used). Possibly even with live ambient audio added. Also factories and office buildings would benefit too, for many of the same reasons (noise, energy use, security, community aesthetics, save space; park cars and trucks on top of it instead of next to it, etc.).

Often, underground living structures are not entirely underground, typically if they are exposed on one side when built into a hill. This exposure can significantly improve interior lighting, although at the expense of greater exposure to the elements.

Structures

There are various ways to develop structures for underground living.

• Caves (Natural) have been used for millennia as makeshift shelter.
• Caves (Constructed)/Dugouts
  Dugout (shelter)
  A dugout or dug-out, also known as a pithouse, pit-house, earth lodge, mud hut, is a shelter for humans or domesticated animals and livestock based on a hole or depression dug into the ground. These structures are one of the most ancient types of human housing known to archeologists...
  
   are a common structure for underground living. Although the tunnelling techniques required to make them have been well developed by the mining
  Mining
  Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
  
   industry, they can be considerably more costly and dangerous to make than some of the alternatives. On the plus side, they can be quite deep. One example would be the town of Coober Pedy
  Coober Pedy, South Australia
  Coober Pedy is a town in northern South Australia, 846 kilometres north of Adelaide on the Stuart Highway. According to the 2006 census, its population was 1,916 . The town is sometimes referred to as the "opal capital of the world" because of the quantity of precious opals that are mined there...
  
   in Australia
  Australia
  Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
  
  , built underground to avoid the blistering heat of the Outback
  Outback
  The Outback is the vast, remote, arid area of Australia, term colloquially can refer to any lands outside the main urban areas. The term "the outback" is generally used to refer to locations that are comparatively more remote than those areas named "the bush".-Overview:The outback is home to a...
  
  .
• Earth Berm structures are essentially traditional homes that have then been buried, typically leaving at least one wall exposed for lighting and ventilation. However, because they are to be buried, the structures must be made of materials capable of surviving the increased weight and moisture of being underground.
• Rammed Earth structures are not truly underground, in the sense of being below grade or buried beneath a berm. Instead, they are structures made of tightly packed earth, similar to concrete
  Concrete
  Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
  
   but without the binding properties of cement
  Cement
  In the most general sense of the word, a cement is a binder, a substance that sets and hardens independently, and can bind other materials together. The word "cement" traces to the Romans, who used the term opus caementicium to describe masonry resembling modern concrete that was made from crushed...
  
  . These structures share many properties with traditional adobe construction.
• Culvert structures are a very simple approach. Large precast concrete
  Precast concrete
  By producing precast concrete in a controlled environment , the precast concrete is afforded the opportunity to properly cure and be closely monitored by plant employees. Utilizing a Precast Concrete system offers many potential advantages over site casting of concrete...
  
   pipes and boxes a few meters across are assembled into the desired arrangement of rooms and hallways onsite, either atop the existing ground or below grade in excavated trenches, then buried. This approach can also be referred to as Cut and Cover.
• Urban underground living is so common that few even think of it as underground. Many shopping mall
  Shopping mall
  A shopping mall, shopping centre, shopping arcade, shopping precinct or simply mall is one or more buildings forming a complex of shops representing merchandisers, with interconnecting walkways enabling visitors to easily walk from unit to unit, along with a parking area — a modern, indoor version...
  
  s are partially or totally underground, in the sense that they are below grade. Though not as exotic as the other underground structures, those working in such urban underground structures are in fact living underground.
• Shaft structures. For example, Taisei Corporation
  Taisei Corporation
  is a Japanese corporation which was established in 1873. Its main areas of business are building construction, civil engineering, and real estate development....
  
   proposed to build Alice City
  Alice City
  Alice City is an underground city that the Taisei Corporation has proposed to build in Tokyo, Japan, as building underground costs less in the now highly built-up Tokyo....
  
   in Tokyo
  Tokyo
  , ; officially , is one of the 47 prefectures of Japan. Tokyo is the capital of Japan, the center of the Greater Tokyo Area, and the largest metropolitan area of Japan. It is the seat of the Japanese government and the Imperial Palace, and the home of the Japanese Imperial Family...
  
   Japan
  Japan
  Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
  
  . The project would incorporate a very wide and deep shaft, within which would be built levels for habitation, all looking in toward a hollow core topped with a huge skylight.
• Tunnels, including storm drains, are used by homeless people as shelter in large cities.

External links

• Mars Foundation
• Bag End 2 - 21st Century Hobbit Hole
• Alice City, Japan
• University of Minnesota Underground Space Center
• The $50 and up underground house book home
• Modern cave construction in Spain
• Stockton Underground : An Owner-Builder Project
• Baldassare Forestiere
• Subterranea Britannica, a society devoted the study and investigation of man-made and man-used underground places.
• Underground home built from "The $50 and Up Underground House" Book. Book Author, Mike Oehler