Everyone knows about the reported recovery of a crashed alien spaceship near Roswell, New Mexico, in July 1947. However, most people are unaware that, at the time of the incident, Roswell Army Airfield was home to the world's only atomic bomber squadron, the 509th Bomb Group. Was this merely a coincidence?During the Cold War, the United States and the Soviet Union built thousands of the far more destructive hydrogen bombs, some of them a thousand times as powerful as the first atomic bombs dropped on Japan. If the nuclear standoff between the superpowers had erupted into World War III, human civilization-and perhaps the very survival of our species-would have been at risk.