For 60 years, the US government has been laying secret doomsday plans to save itself in the event of nuclear war — even while the rest of us die. Today, a third generation of doomsday planners are settling into life inside a network of bunkers that are staffed 24 hours a day, 365 days a year, ready to house top government officials in the event of catastrophe. How did these Cold War-era plans come together, how have they evolved over time, and how prepared are we for a worst-case scenario?