Covering an area of 85 square kilometers and containing 1,000 anti-air raid structures , the subterranean complex was said to have been mostly hand-dug by 300,000 local residents . `` The plan was to move half of Beijing 's population underground and the other half to western hills in the event of a nuclear attack , '' Frisch explained . The 22-year-old New York native has lived in China on and off for a year and is fascinated by the bomb shelter and its history . After the authorities opened part of the Underground City as a tourist attraction to woo foreigners , he turned a routine visit to an adventure in 2006 . Armed with a flashlight , Frisch veered off from the mandatory guided tour . Moving sandbags and unchaining doors , he explored the off-limit area and found rooms with bunk beds and decayed cardboard boxes of water purifiers . `` It 's more than just propaganda posters down there -- it really is a parallel universe , with street signs stenciled on the wall , '' Frisch said . Since then , Frisch has discovered other shelters linked to the network -- many of them turned
BEIJING , China -LRB- CNN -RRB- -- Walking through a maze of narrow streets south of Tiananmen Square , Nick Frisch appeared unfazed by the sight of drastic changes -- traditional courtyard houses that once lined up these hutongs , or alleys , now in different stages of being knocked down . Nick Frisch 's underground exploration in Beijing has attracted the attention of a Singapore TV crew . While the Qianmen area is going through an extreme makeover -- a restoration of its Qing dynasty flavor ahead of the Olympics -- Frisch 's destination is safe from the city 's ubiquitous wrecking balls . Upon reaching the entrance to the Underground City , however , he was told it was closed for `` renovation , '' just like the surrounding neighborhood . `` It 's like they 're trying to literally bury this place before the Games , '' said Frisch , a recent graduate of Columbia University in the United States , with a major in history and Chinese language . This place is a vast network of tunnels built beneath Beijing 's city center during the 1970s in anticipation of a nuclear war with the Soviets .