- The 816 Nuclear Military Plant, located in China’s Chongqing municipality, used to be a top-secret hideout
- It was designed to manufacture nuclear plutonium in the 1960s but was stopped from doing so in 1984
- For the first time, foreign tourists are invited to explore its vast winding caves and modern light displays
It could be straight out of a Bond movie.
This vast underground cavern, formally a top-secret Chinese nuclear base, has finally opened for tourists to have a poke around.
Hailed as the largest man-made cave in the world, the 816 Nuclear Military Plant, located in the mountains of Fuling district in China’s Chongqing municipality, was designed to manufacture plutonium in the 1960s – a 17-year project involving more than 60,000 soldiers.

Yan
Yang Yan, an administrator at the site, told China Daily: ‘So far, no foreigners have visited the plant. A tour takes three hours, and visitors must follow the guide, otherwise they will get lost in this maze-like cave.’
The enormous space spans more than 12 miles, with 18 main caves and more than 130 roads and tunnels, which vehicles are free to pass through.
It was designed to tolerate thousands of tons of TNT explosives, and at least 100 workers were reported to have died during construction.
These days, it’s been renovated to feature colourful modern lighting, as well as educational displays. And visitors need not fear for their safety.
‘This base has never been put into operation or stored any nuclear material,’ Mr Yang said. ‘There is no need to worry about radiation. It is safe to enter.’
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