Jennifer Ouellette in Ars Technica:
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. Less well-known but equally significant from a nuclear arms race standpoint was the Soviet Union’s successful detonation of a hydrogen “superbomb” in the wee hours of October 30, 1961.
Dubbed “Tsar Bomba” (loosely translated, “Emperor of Bombs”), it was the size of a small school bus—it wouldn’t even fit inside a bomber and had to be slung below the belly of the plane. The 60,000-pound (27 metric tons) test bomb’s explosive yield was 50 million tons (50 megatons) of TNT, although the design had a maximum explosive yield of 100 million tons (100 megatons).
More here.