Are there any underground cities known except those found in Cappadocia?

Question

I've recently read the story about the discovery of the underground city of Derinkuyu. Now I'm a bit curious if there are other similar archaeological discoveries: I mean something we could really call a city, a place where many people would be able to live for a long while (at least a month) and deal a "normal" life. My first steps and researches lead me to rather "Modern" underground cities such as Coober Pedy, the Wieliczka Salt Mine, Dìxià Chéng and a couple of malls which have been built in the underground of bigger cities. But what I'm looking for is something that is much older (middle age or earlier).

Strictly speaking "City" is somewhat incorrect, but I think it is clear what I mean a refuge which is big and well equipped enough to accommodate a lot of people for a longer duration and where they could still deal a good life. About Derinkuyu they pretended that the people where able to go ahead with their trade, handcraft and even gather their live stock inside this labyrinth. That staying there for a very long time would have effects on ones health is clear.

Answer 1

There are a few underground cities that I can think of, some may fit your requirements better than others. If you consider tunneling into rocks, then Petra would be a very large city that was built into the cliffs and ground. If you are only considering cities that are entirely under the ground, Naours France has an underground city that was built in an old Roman quarry and occupied in the middle ages. It has enough space to host several thousand people and several churches, wells, bakeries, wine presses, etc...

Answer 2

Dating in its origins from the 2 millenium BCE and still inhabited by up to 40 million people today:

The first type of yaodong were underground dwellings that date back to the 2nd millennium BC, China's Bronze Age, and according to Chinese tradition, the Xia Dynasty. Chinese scholars generally believe that this type of habitat has developed mainly from the Han dynasty (206 BC to 220 AD), along with a progressive improvement of construction techniques to the dynasties Sui (581 to 618) and Tang (618 to 907). But it is during the dynasties Ming (1368 to 1644) and Qing (1644 to 1912) that the pace of construction reached its peak.


_{Source: Wikipedia – Yaodong}

The number of 40 million is a quote from the Wikipedia page, which relies on:

In northern China, an estimated 40 million people currently live in cave homes known as yaodong. As the human population of the entire planet in 8,000 BC was probably only five million, there are eight times as many cavemen now than there were people of any kind then.
_{Source: "Where did Stone Age people live?" in: John Lloyd and John Mitchinson: "The Book of General Ignorance. The Noticeably Stouter Edition", Faber and Faber: Londom, 2010.}

While the exact number of people living in these kind of structures may be hard to ascertain, the order of magnitude seems to check out:

Some 30 million Chinese still live in caves and over a 100 million people reside in houses with one or more walls built in a hillside. Many of the cave and hill dwellings are in the Shanxi, Henan and Gansu provinces. Caves are cool in the summer, warm in the winter and generally utilize land that can not be used for farming. On the down side, they are generally dark and have poor ventilation. Modern caves with improved designs have large windows, skylights and better ventilation. Some larger cave have over 40 rooms. Others are rented out as three-bedroom apartments.
_{Source: Facts and Details: Cave Homes and Ant People in China, that number is apparently based on: Ronald G. Knapp: "Chinese Landscapes The Village as Place", University of Hawaii Press: Honululu, 1992, p25.}

A "Remarkable aerial pictures reveal China's 'invisible village' where local residents live in subterranean caves - a lifestyle they have kept for 4,000 years" (DailyMail.UK, 5 April 2016) for one conglomeration with 10000 homes:

Answer 3

Nushabad in Iran was apparently used to avoid Mongol invasions (13th Century), but is perhaps older as artefacts from earlier periods have been found within. It is not clear how long people stayed down there, but there is an extensive ventilation system to allow fresh air within the underground city.

Answer 4

中洞 village in 安顺 prefecture is the largest current cave city by year-round population, with a population of around 100. The village dates back to either the Chinese communist revolution or hundreds of years before that, depending on who you ask. As other answers have noted the practice of cave housing is not unusual in China (with tens of millions of people currently living in caves), and dates back to around 2000 BC. Nonetheless, most cave housing is part of a larger, non-subterranean settlement. 中洞 is unusual in that the settlement itself is exclusively subterranean, excepting the remnants of (thus far unsuccessful) government efforts to end the practice.