World’s Largest Manmade Cave Opens to Tourists for the First Time in Chongqing

Visitors to Chongqing can now explore what used to be an underground nuclear plant, dubbed the world’s largest manmade cave at a size of 1.1 million square feet (or about 20 football fields). 

The abandoned 816 Nuclear Military Plant is open to foreign visitors for the first time after undergoing renovations, construction of a new nuclear science center, and various sections explaining the history behind the base. 

Inside, visitors can explore more than 12 miles of caves, with more than 130 different roads, tunnels, and shafts. 

The largest cave—the nuclear reactor hall—is more than 262 feet high and 82 feet wide.