Fifty years have passed since the Cheyenne Mountain Complex went fully operational. Now, the US Air Force has given us a chance to look inside the legendary military installation made famous by the Terminator series [update: and by Stargate SG-1!].
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.