According to Eric Schlosser in his follow-up to Fast Food Nation, Command and Control, days after the inauguration of John F. Kennedy in 1961, the American military came with in a "hair's breadth" of detonating a nuclear explosion over North Carolina.
A pair of Mark 29 hydrogen bombs -- each of which was 250 times more powerful than the bomb that leveled Hiroshima -- were accidentally deployed when the B-52 hauling them went into an uncontrolled spin.
One of them fell to the ground unarmed, but the failsafe mechanisms in the other underwent a cascade of failure:
The arming wires were yanked out, and the bomb responded as though it had been deliberately released by the crew above a target. The pulse generator activated the low-voltage thermal batteries. The drogue parachute opened, and then the main chute. The barometric switches closed. The timer ran out, activating the high-voltage thermal batteries. The bomb hit the ground, and the piezoelectric crystals inside the nose crushed. They sent a firing signal.
Had the bomb exploded, the lethal fallout would have spread across the Eastern Seaboard, blanketing New York and Washington D.C. The near-destruction of the Eastern Seaboard should serve as a warning to a generation that has, according to Schlosser, by and large forgotten the danger posed by nuclear weapons:
As the decades passed, particularly since the Second World War, we lost the sense of how devastating these weapons can be—and also what its like to be in a society that's been completely destroyed by warfare. We're very fortunate in the United States that we've been protected by geography. I was in Manhattan on 9/11, and the difference between having 3,000 Americans killed, which was horrible on 9/11, versus 500,000 or a million is almost impossible to comprehend. These weapons are machines, and I think they are the most dangerous machines ever invented. And like every machine, sometimes they go wrong.
Schlosser's book, Command and Control, will be available in bookstores and for download on September 17.