Built back in the Cultural Revolution and able to keep millions of Beijingers, Beijing's Underground City, a bomb shelter just beneath the ancient capital's downtown area, has been virtually forgotten by local citizens, despite being well-known amongst foreigners since it officially opened in 2000.

Longer than the Great Wall of China. Stretches to five cities in China: Beijing, Shanghai, Xian, Tianjin and Nanjing. The Underground City has also been called the Underground Great Wall. This subterranean complex is a relic of the Sino-Soviet conflict in 1969, a time when Mao Zedong ordered the construction of the underground bomb shelters complex in the event of a Soviet attack.

Built from 1969 to 1979 by more than 300,000 local citizens and even school children. Room to house 300,000 people. Contains facilities such as stores, restaurants, clinics, schools, theaters, reading rooms, factories, a roller skating rink, a grain and oil warehouse as well as barber shops and a mushroom cultivation farm, for growing foods that require little light. Vehicular access and cell phone access is ok even 80m below the surface. Secret, underground access to key sites around Beijing: Temple of Heaven, Tiananmen Square, Forbidden City, and Beijing Capital International Airport.

Mao's slogan calling for people to dig deep, prepare provisions and not to seek hegemony is printed on the wall. The temperature is said to be at a constant 27 degree celsius. It is mentioned that Mao and other leaders had a separate passage way to take them out of the city in the event of an attack on Beijing.

An advanced ventilation system to protect against chemical attack, and allows for fresh air for seniors suffering from rheumatism and asthma. Large metal doors are also part of the protection against floods or attacks from the enemy. Around a thousand anti-air raid structures include.

For those interested to see part of the Underground City, the address is 62 West Damochang Street, Qianmen, Tel. 6702-2657, 6701-1389. Apparently, another site is at Beijing Qianmen Carpet Factory at 44 Xingfu Dajie, Chongwen District, Tel. 6701-5079. One can also try a lesser known site at 18 Dazhalan Jie at Qianmen.