In 1969, Chairman Mao began work on a giant bunker beneath the city of Beijing to house the city's population in the event of a nuclear attack. The underground city was never operational, but the tunnels and facilities still remain.
Fearing a nuclear or other attack from the Soviet Union, Mao commissioned the construction of Dixia Cheng, which was built to hold restaurants, clinics, facilities for underground agriculture, and even a roller skating rink. Although the claim was never tested, the Chinese government claimed that Dixia Cheng could have housed Beijing's entire six million person population. Although some of the rooms and tunnels have been used for various purposes — public meeting spaces, government storage, hostels, a tourist attraction — but many of the tunnels have been boarded up or neglected. Still, some people apparently live in the portions of the tunnels not maintained by the government. Viceland visited some of the more neglected portions of the Dixia Cheng tunnels, and you can see more of the photos here.