Enlarge / The mushroom cloud from the Soviet detonation of "Tsar Bomba" on October 30, 1961, was so large that the photographers had a hard time capturing its full dimensions. (credit: Rosatom) The detonation of the first nuclear bombs over Hiroshima and Nagasaki in August 1945 is seared into our collective memory, and the world has been haunted by the prospect of a devastating nuclear apocalypse ever since.