Extra: American Doomsday

America's Doomsday plan. It's the government's ultimate playbook, with a strategy for even the darkest hours—developed when Cold War tensions were high, but never used until 9/11. In American Doomsday, fly in an E4-B—the president's command, control, and communications center for times of national catastrophe; go inside the secret bunker used by government officials on September 11; and witness how the luxurious Greenbrier Resort became a critical, top secret congressional bunker.