Every day in Washington, DC, the blue-and-gold 1st Helicopter Squadron, codenamed "MUSSEL," flies over the Potomac River. As obvious as the Presidential motorcade, most people assume the squadron is a travel perk for VIPs. They're only half right: while the helicopters do provide transport, the unit exists to evacuate high-ranking officials in the event of a terrorist or nuclear attack on the capital. In the event of an attack, select officials would be whisked by helicopters to a ring of secret bunkers around Washington, even as ordinary citizens were left to fend for themselves. For sixty years, the US government has been developing secret Doomsday plans to protect itself, and the multibillion-dollar Continuity of Government (COG) program takes numerous forms -- from its plans to evacuate the Liberty Bell from Philadelphia to the plans to launch nuclear missiles from a Boeing-747 jet flying high over Nebraska. In Raven Rock, Garrett M. Graff sheds light on the inner workings of the 6