Inside the Chongqing mountains, China has secretly built a nuclear bunker to manufacture Plutonium and other cold-war explosives. This plant was named as 816 Nuclear Military Plant and contains man-made caves interconnected, tunnels and roads.
Besides, the world’s largest artificial cave of 80m height and 25m width. Recently in October, China has opened this bunker to the public.
Around 60,000 chinese soldiers were involved in its construction in 1966 and a ton of them deceased during the process. It was planned to manufacture Plutonium-239 which is used in nuclear weapons. But the fortunate thing is, China withdrew its nuclear plans in 1984 that this plant was never used at all.
As it was declassified in 2002, it was renovated and made a science center and a tourist attraction.