Atomic Bombs   were exploded over Hiroshima ( right ) and Nagasaki to end World War 2. Nagasaki's Fat Man was 40% more powerful than Hiroshima's Little Boy.  The Tsar Bomba of the Soviet Union, a hydrogen bomb, was 3500 times more powerful than Fat Man. Watch this fascinating  video of how much destruction these weapons would cause . Comparison with other bombs, height of Mount Everest and altitude of commercial airliner. It is reported, that Soviet scientists were worried about this H-Bomb being, perhaps, too powerful, so they decided to limit the size to 50 Megatons, but instead got 57 MT of TNT.  They could have brought it up to more than 100 MT. Can a more powerful bomb be built?  Yes, an  anti-matter bomb.  Watch this video. Theoretically, should be 100 times more powerful than a Tsar Bomba. Just half a gram of anti-matter reacting with half a gram of ordinary matter would produce the equivalent of the Nagasaki A-Bomb. A ton of anti-matter ...