Hiroshima was destroyed by the first atomic bomb used in warfare on 6 August 1945.
The United States dropped a uranium gun-type weapon, code-named Little Boy, from the B-29 bomber Enola Gay. The bomb exploded over Hiroshima at about 8:15 a.m. local time, causing massive destruction and killing or fatally injuring many people immediately and in the months that followed.
Hiroshima was selected partly because it was a military headquarters and an important industrial and transportation center. It had also remained comparatively undamaged by earlier conventional bombing, allowing the effects of the new weapon to be measured more clearly.
The bombing did not produce an immediate Japanese surrender. Nagasaki was bombed three days later, on 9 August, while the Soviet Union also entered the war against Japan. Japan announced its acceptance of the Potsdam Declaration on 15 August and signed the formal surrender document on 2 September.