Buried 100 meters (328 feet) underground, the Pyongyang Metro is one of the deepest commuter systems in the world.
원문출처 : http://www.cnn.com/2016/11/06/design/north-korea-subway-commute/index.html
원문출처 : http://www.cnn.com/2016/11/06/design/north-korea-subway-commute/index.html