816 Nuclear Military Plant

The 816 Nuclear Military Plant is a massive underground nuclear weapons production facility located in China, near the coordinates 40.7000926,100.6595304. This unfinished military megaproject represents one of the most ambitious Cold War-era construction efforts, designed to produce plutonium for nuclear weapons during a period of heightened tensions with the Soviet Union. The facility contains the world's largest artificial cave and comprises an extensive network of 17 man-made caves connected by tunnels stretching over 20 kilometers.