USA PHOTO ESSAY COG
The B entrance portal into Raven Rock Mountain Complex, a massive, 650-acre nuclear bunker and national security site built inside a hollowed-out mountain near Blue Ridge Summit, Pennsylvania, USA 28 February 2018. Constructed during the Cold War, the facility was conceived as a backup for the Pentagon and built to house military leadership, as well as the president, in the event of a nuclear disaster. Entry is through one of four portals, each protected by a 34-ton blast door.