World War II - Hiroshima, Nagasaki, Atomic Bombs: On August 6, 1945, an atomic bomb was dropped on Hiroshima: the combined heat and blast pulverized everything in the explosion's immediate vicinity and immediately killed some 70,000 people (the death toll passed 100,000 by the end of the year). A second bomb, dropped on Nagasaki on August 9, killed between 35,000 and 40,000 people, injured a like number, and devastated 1.8 square miles.