The Raven Rock Mountain Complex (RRMC), also known as Site R and nicknamed 'The Rock,' is a highly classified U.S. military installation featuring an extensive underground nuclear bunker near Blue Ridge Summit, Pennsylvania. Built in the early 1950s during the Cold War, this facility serves as a Continuity of Government (COG) site designed to house and protect key government and military personnel in the event of a catastrophic nuclear, chemical, or other devastating attack on the United States.
The underground complex contains emergency operations centers for the United States Army, Navy, Air Force, and Marine Corps, earning it the moniker 'underground Pentagon.' Located beneath Raven Rock Mountain, the bunker is fully operational and would serve as a central command center for defense operations should nuclear war break out. The facility represents one of the most extensive government survival measures undertaken during the Cold War era, reflecting the strategic importance placed on maintaining governmental continuity during the height of nuclear tensions.