The Pyongyang Metro is the deepest in the world, buried 100 meters below the surface, which means it conveniently doubles as a nuclear bunker. It mostly operates on the west bank of Pyongyang with 17 stops on two lines. It was first opened in 1973, and the last station was added to line 1 in 1987. Before 2010 tourists were only allowed to travel between Puhŭng Station and Yŏnggwang Station, sparking a conspiracy theory that the two stations comprised the entire system. Here’s a rare glance into the underground life of the North Korean capital.