At 0816 hours 6 August 1945, one of three B-29s over Hiroshima dropped the first atomic bomb ever used for military purposes. An eyewitness who was 2% miles west of the city stated:
“I saw a single enemy airplane flying over Hiroshima. It dropped or fired a brilliant object. I thought at first that it was an incendiary bomb, but then I saw what looked like a smoke ring from a funnel, gradually falling toward the ground. It grew larger almost immediately and increased in brilliance and soon covered an area almost as big as the city. A flame appeared which was even brighter than the sun. I thought I might get hurt so I fell flat on the ground.”
Exploding in the air 2,000 feet above a post office slightly northwest of the heart of the city, the atomic bomb achieved an intensity unparalleled in the history of destruction by a single man-made weapon. As estimated and described by scientists the nuclear-fission bomb had changed into a fireball hotter than the center of the sun (70,000,000°C) during the detonation that was over in a millionth of a second. It emitted radiations ranging from beyond the heat bands of infrared, down through the visible spectrum and into the ultraviolet and penetrating gamma rays. The radiations were of an intensity without precedent in human experience. Pressures developed in the bomb were of the order of a thousand billion times atmospheric pressure.
Barnett, Erin, and Philomena Mariana, eds., Hiroshima: Ground Zero 1945. New York: International Center of Photography, 2011, p. 10.
Unidentified Photographer, [Ruins of Hiroshima Prefectural Commercial Exhibition Hall, Building No. 4, (Atomic Bomb Dome)], October 24, 1945 (2006.1.33)
The building was constructed in 1915 as Hiroshima Prefectural Commercial Exhibition Hall. In 1921, the name changed to Hiroshima Prefectural Products Exhibition Hall and again in 1933 to Industrial Promotion Hall. Besides displaying and selling products from around the prefecture, it also served as a history and art museum. As the war intensified, these roles withered and various government offices took over the space, including the Chugoku-Shikoku Public Works Office of the Home Ministry and the Lumber Control Corporation. The atomic bombing killed everyone in the building. Because the bomb exploded virtually overhead, it retained the distinctive feature that earned it the name “Atomic Bomb Dome” [The Hiroshima Peace Memorial Museum (Genbaku Dome)] after the war. (2006.1.33)
Unidentified Photographer, [Ruins of Shima Surgical Hospital, Hiroshima], October 24, 1945 (2006.1.32)
Building 5. Looking west showing debris of building in foreground and Building No. 4 in center background. Combustible debris completely burned. Hiroshima: Ground Zero 1945, p.9
Unidentified Photographer, [Ruins of Hiroshima Prefectural Commercial Exhibition Hall, Building No. 4, (Atomic Bomb Dome)], November 14, 1945 (2006.1.34)
Unidentified Photographer, [Ruins of Hiroshima Prefectural Commercial Exhibition Hall, Building No. 4, (Atomic Bomb Dome)], November 14, 1945 (2006.1.36)
The United States detonated an atomic bomb 2,000 feet above Hiroshima, a city of over 350,000 inhabitants, on August 6, 1945. The above photos, once-classified by the U.S. government, were made to record the destruction as part of the United States Strategic Bombing Survey. “The goal of the Survey’s Physical Damage Division was to photograph and analyze methodically the impact of the atomic bomb on various building materials surrounding the blast site, the first ‘Ground Zero.’” Hiroshima: Ground Zero 1945.
Building No. 4, the Hiroshima Prefectural Commercial Exhibition Hall, was the closest building to hypocenter (ground zero). The distance from the hypocenter was approximately 160m. It is now the Hiroshima Peace Memorial Museum.