Hiroshima was the target of the first atomic bomb used in warfare in 1945.
On August 6, 1945, the U.S. B-29 bomber Enola Gay dropped the uranium gun-type bomb Little Boy over Hiroshima. The explosion devastated the city and killed tens of thousands of people immediately or soon afterward. Many more died over the following months from burns, injuries, radiation sickness, and other effects.
Nagasaki was bombed three days later, on August 9, with the plutonium implosion bomb Fat Man. Hiroshima was therefore the first city attacked with a nuclear weapon, while Nagasaki was the second. The bombings occurred alongside the Soviet declaration of war and invasion of Japanese-held Manchuria. Japan announced its decision to surrender on August 15 and signed the formal surrender document on September 2.