The Raven Rock Mountain Complex , also known as Site R, is a U.S. military installation with an underground nuclear bunker near Blue Ridge Summit, Pennsylvania, at Raven Rock Mountain that has been called an "underground Pentagon". The bunker has emergency operations centers for the United States Army, Navy, Air Force and United States Marine Corps. Along with Mount Weather Emergency Operations Center in Virginia and the Cheyenne Mountain Complex in Colorado, it formed the core bunker complexes for the US Continuity of Government plan during the Cold War to survive a nuclear attack