Two Mark 39 hydrogen bombs were ejected from a B-52 bomber over North Carolina in January 1961 when the bomber broke up in mid-air. One of the bombs armed itself and prepare to detonate as it drops towards the ground.
The East Coast of the United States was spared from a nuclear disaster as a safety device in the bomb prevented the detonation.
[thumb]http://www.theguardian.com/world/2013/sep/27/atomic-bomb-north-carolina-video[/thumb]