Underground city

An underground city is a series of linked subterranean spaces that may provide a defensive refuge; a place for living, working or shopping; a transit system; mausolea; wine or storage cellars; cisterns or drainage channels; or several of these. The term may also refer to a network of tunnels that connects buildings beneath street level., which may house office blocks, shopping malls, metro stations, theatres, and other attractions. These passages can usually be accessed through the public space of any of the buildings connecting to them, and sometimes have separate entries as well. This latter definition encompasses many modern structures, whereas the former more generally covers tunnel systems from ancient times to the present day.

Underground cities are especially functional in cities with very cold or hot climates, because they permit activities to be comfortably accessible year round without regard to the weather. Underground cities are similar in nature to skyway systems and may include some buildings linked by skyways or above-ground corridors rather than underground.

Underground City, Montreal

Montreal's Underground City (officially RÉSO or La Ville Souterraine in French) is the set of interconnected complexes (both above and below ground) in and around Downtown Montreal, Quebec, Canada.

Not all portions of the indoor city (ville intérieure) are underground. The connections are considered tunnels architecturally and technically, but they are air-conditioned and have lighting as good as any building's livable space does. Many tunnels are large enough to have shops on both sides of the passage. With over 32 km (20 mi) of tunnels spread over more than 12 km² (4.6 sq mi), connected areas include shopping malls, apartment buildings, hotels, condominiums, banks, offices, museums, universities, seven Metro stations, two commuter train stations, a regional bus terminal, and the Bell Centre amphitheatre and arena. There are more than 120 exterior access points to the underground city. Each access point is an entry point to one of 60 residential or commercial complexes comprising 3.6 km² (1.4 sq mi) of floor space, including 80% of all office space and 35% of all commercial space in downtown Montreal. In winter, some 500,000 people use the underground city every day.

Underground City (Beijing)

The Underground City (Chinese: 地下城; pinyin: Dìxià Chéng) is a Cold War era bomb shelter consisting of a network of tunnels located beneath Beijing, China. It has also been referred to as the Underground Great Wall since it was built for the purpose of military defense. The complex was constructed from 1969 to 1979 in anticipation of a nuclear war with the Soviet Union, as Sino-Soviet relations worsened and was officially reopened in 2000. Visitors were allowed to tour portions of the complex, which has been described as "dark, damp, and genuinely eerie". Dixia Cheng has been closed for renovation since at least February 2008.

Location

The tunnels of the Underground City run beneath Beijing's city center, covering an area of 85 square kilometres (33 sq mi) 8 to 18 metres (26–59 ft) under the surface. At one time there were about 90 entrances to the complex, all of which were hidden in shops along the main streets of Qianmen. Many of the entrances have since been demolished or blocked off for reconstruction. Known remaining entrances include 62 West Damochang Street in Qianmen, Beijing Qianmen Carpet Factory at 44 Xingfu Dajie in Chongwen District, and 18 Dazhalan Jie in Qianmen.