On October 30, 1961, the former Soviet Union detonated the 'Tsar Bomba' - world's largest nuclear weapon test in history. The 27-ton hydrogen bomb had a yield of 50 megatons of TNT, around 1,400 times stronger than the Hiroshima and Nagasaki nuclear bombs combined. The explosion generated a mushroom cloud 7 times higher than the Mount Everest.