BEIJING, China (CNN) -- 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. 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 to cheap hostels -- on busy streets. Not surprisingly, the time-warped part of the Underground City remains his favorite.



"I sometimes wish I was born earlier to witness the Cold War unfold -- and the tunnels have given me a unique vantage point to look into that period of history," Frisch said.



"While Beijing is transforming itself for the Olympics, it's just amazing to see this space in such a sharp contrast to the city aboveground." E-mail to a friend



Steven Jiang is a Beijing-based freelance writer and former CNN producer.
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