The Tsar Bomba is the single most physically powerful device ever deployed on Earth . For comparison , the largest weapon ever produced by the U.S. , the now-decommissioned B41 , had a predicted maximum yield of . The largest nuclear device ever tested by the U.S. ( Castle Bravo ) yielded because of an unexpectedly high involvement of lithium-7 in the fusion reaction ; the preliminary prediction for the yield was from . The largest weapons deployed by the Soviet Union were also around ( e.g. , the SS-18 Mod . 3 warhead )
Castle Bravo
Castle Bravo
Tsar Bomba