Hiroshima was struck by the “Little Boy” atomic bomb on August 6, 1945.
The weapon was carried by the B-29 bomber Enola Gay and detonated over Hiroshima at approximately 8:15 a.m. local time. Little Boy was a uranium-based gun-type nuclear weapon developed by the Manhattan Project. Its use marked the first wartime deployment of a nuclear weapon.
Three days later, the United States dropped the plutonium-based Fat Man bomb on Nagasaki. The two attacks caused enormous destruction and loss of life, though historians continue to debate their relative importance alongside the Soviet entry into the war and Japan’s internal political crisis.
Hiroshima had been selected because it was a large urban and military-industrial center that had suffered comparatively little earlier bombing. The city’s destruction became a central event in Japan’s decision to accept the Potsdam Declaration and surrender.