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Underground city

Underground city is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Underground city rather than just read about it. In short: 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. Underground cities may be currently active modern creations or they may be historic including ancient sites, some of which may be entirely or partially open to the public.

Underground city — main illustration
Underground city — illustration

Key takeaways

  • Underground city belongs to engineering; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Underground city to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Underground city from memory before moving on to harder problems.

Reference excerpt

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. Underground cities may be currently active modern creations or they may be historic including ancient sites, some of which may be entirely or partially open to the public. The term may also refer to a network of tunnels that connects buildings beneath street level that may house office blocks, shopping centres, 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. Some cities also have tunnels that have been abandoned.

Asia

China Beijing built an extensive tunnel network called the Underground City (Chinese: 地下城; pinyin: Dìxià Chéng) during the Sino-Soviet conflict, supposedly covering 85 km2, falling into disuse in the 1970s. It was opened in 2000 to the public and tourists, but closed in 2008 for renovations. As of 1 July 2009, all "official" remaining entrances appear to be closed. Guangzhou has at least 16 different underground networks. The largest underground network is in Zhujiang New Town. It connects the commercial basements of over 35 office towers and malls surrounding the Zhujiang New Town Central Park, and extends to Zhujiang New Town, Guangzhou Women and Children's Medical Center, Huangpu Dadao and Huacheng Dadao metro stations. The mall portion under the Zhujiang New Town Central Park alone totals at least 150,000 square metres (1,610,000 sq ft) of commercial space. In addition there are large subterranean retail tunnels that surround several Guangzhou Metro stations such as Tiyu Xilu, Tianhe Sports Center, Martyrs' Park, Guangzhou railway station and Guangzhou East railway station. Smaller networks of subterranean retail tunnels surround several Guangzhou Metro stations such as Chen Clan Academy, Jiangnan West (江南新地商业街), Gongyuanqian Harbin has a number of large, multi-level underground shopping areas, originally built for air defense. The largest is at the roundabout intersection of Xida Zhi street and Hongjun street where three levels of markets following streets from four directions meet under the giant snowflake atrium. Hangzhou has an underground mall in Wulin Square connected to a subway station of the same name and nearby office buildings. Nanjing has an underground mall around Xinjiekou metro station. Qingdao has two small underground shopping areas, one at the head of the Zhanqiao (pier) and one west of the Qingdao guest house. Shanghai has a few underground networks, most notably at People's Square metro station, wherein the line 2 station has a second mezzanine full of shops and Line 1 is connected to a large underground shopping gallery at its south end. Shanghai Science Museum stop on line 2 has a large underground shopping area, known for its imitation goods. Huangpi Road South and Xujiahui stations are directly connected to shopping centers, and the Lujiazui station is connected to the Bank of China tower. Shenzhen has quite a few underground shopping malls: The largest system is Link City (simplified Chinese: 连城新天地; traditional Chinese: 連城新天地), an underground shopping plaza connecting Convention and Exhibition Center, Shopping Park, Futian and Gangxia stations with surrounding office buildings. The initial sections of the mall used to be an air-raid shelter. In 2022, the network was expanded to Gangxia North station via the basement of the One Avenue mall. An underground electronics market connecting Huaqiang Road, Huaqiang North and Huaxin stations and the surrounding Huaqiangbei electronics markets. Smaller networks of subterranean retail tunnels surround several Shenzhen Metro stations such as Chegongmiao, Laojie, Science Museum, Luohu, Huangbeiling, Guiwan, Nanshan Book Mall, and Window of the World. Wuhan has a number of subterranean retail tunnels surrounding Wuhan Metro stations such as Zhongshan Park, Wuhan Business District, Wangjiawan, Qushuilou, Xudong, Wangjiadun, Hongshan Square and Changgang Road Stations.

Hong Kong Many MTR stations in Hong Kong form extended underground networks connecting to adjacent buildings and at the basement of some major shopping malls in the area above. In addition, the stations themselves often house a number of retail shops. Among such, the largest underground network consists of numerous out-of-system passageways within the station complex connecting the Tsim Sha Tsui–East Tsim Sha Tsui stations, government-owned pedestrian underpasses and basements of shopping malls, including the K11 Art Mall. In whole, the underground network spans almost the entirety of the retail heart of Tsim Sha Tsui, from Canton Road to the West and Chatham Road South to the East, and from Victoria Harbour to the South and Cameron Road to the North. Previously, additional underground networks have been proposed for Causeway Bay in 2006 and in Kwun Tong under Hoi Yuen Road in 2010. As of 2014, studies are underway for underground networks in Tsim Sha Tsui, Kowloon Park, Victoria Park, Causeway Bay, Happy Valley, Admiralty, Wan Chai and Hong Kong Park. However, as of 2024, only the network in Tsim Sha Tsui had been built. In 2017, The Development Bureau announced that two underground streets will be constructed in Kowloon City District, which would connect Kowloon City, San Po Kong, Kai Tak station and Sung Wong Toi station. The system would be known as Kai Tak Underground Shopping Street. As of 2025, the only portions constructed and operational are the basement portion of the AIRSIDE mall and the Cullinan Sky Mall, both of which connect to Kai Tak Station.

Iran Historical underground cities of Persia include Samen, Nushabad, and Kariz.

… excerpt ends here. Continue reading the full article.

Illustrations

Underground city: Tenjin Underground City in Chūō-ku, Fukuoka, Fukuoka Prefecture, Japan
Tenjin Underground City in Chūō-ku, Fukuoka, Fukuoka Prefecture, Japan
Underground city: Shiodome City Center underground in Minato, Tokyo, Japan
Shiodome City Center underground in Minato, Tokyo, Japan
Underground city: Tenjin Underground City in Chūō-ku, Fukuoka, Fukuoka Prefecture, Japan
Tenjin Underground City in Chūō-ku, Fukuoka, Fukuoka Prefecture, Japan
Underground city: An underground mall in Taipei connecting two Taipei Metro stations
An underground mall in Taipei connecting two Taipei Metro stations
Underground city: A typical view from inside the underground city in Derinkuyu, one of the largest underground complexes in Cappadocia. There are few artifacts left from the original builders, mainly just large rocks that were used to block the passage for intruders. Most of the "cities" are corridors, but some places there are rooms large enough to live in, and some rooms that have the cross-like shape of a church, which is probably exactly what they were.
A typical view from inside the underground city in Derinkuyu, one of the largest underground complexes in Cappadocia. There are few artifacts left from the original builders, mainly just large rocks that were used to block the passage for intruders. Most of the "cities" are corridors, but some places there are rooms large enough to live in, and some rooms that have the cross-like shape of a church, which is probably exactly what they were.

Worked examples

Example 1 — a first encounter with Underground city

Start with the simplest possible case. Write down what Underground city claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Underground city before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Underground city ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Underground city

In research
Underground city appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Underground city in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Underground city is common in secondary-school and first-year university syllabi. It links to neighbouring topics Pedestrian infrastructure, Types of cities, Underground cities, so understanding it makes those chapters shorter.
In everyday life
Look for Underground city outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Underground city in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Underground city means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Underground city out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Underground city in simple terms?

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. Underground cities may be currently active modern crea…

Why does Underground city matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Underground city?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Underground city.

Tags

  • Pedestrian infrastructure
  • Types of cities
  • Underground cities
  • Urban exploration

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