At 8:15am on 6 August 1945, a nuclear bomb nicknamed "Little Boy" was dropped on Hiroshima by an American B-29 Superfortress bomber, the Enola Gay, flown by Colonel Paul Tibbets.
The blast and subsequent fire devastated an area of five square miles (13 square kilometres). More than 60% of the city's buildings were completely destroyed.
An estimated 80,000 people died immediately, but injuries and radiation took the final death toll to around 140,000 from Hiroshima's population of 350,000.
Three days later, a larger bomb nicknamed "Fat Man" was dropped on the city of Nagasaki. Japan surrendered, ending the Second World War.
Left: Colonel Paul W Tibbets Jr, pilot of the Enola Gay, the plane that dropped the atomic bomb on Hiroshima, waves from the cockpit before take-off. Right: The atomic bomb, nicknamed Little Boy, is seen just before being loaded into Enola Gay's bomb bay.(Getty)
An atomic cloud mushrooms over Hiroshima, in this photo taken from the Enola Gay flying over Matsuyama, Shikoku(National Archives)
Aerial views of the city of Hiroshima before and after the atomic bomb was dropped(National Archives)
An aerial view of Hiroshima showing the devastation caused by a single atomic bomb(Getty)
September 1945. The remains of the Prefectural Industry Promotion Building, which was later preserved as the Hiroshima Peace Memorial, Atomic Bomb Dome or Genbaku Dome(AFP)
August 1945: The twisted wreckage of a theatre, located 800 metres from the epicentre of the atomic explosion(Getty)
A burnt-out fire engine is seen in the rubble(Getty)
People walk along a road through the devastated city(AFP)
American bomber pilot Paul Tibbets (centre) stands with the ground crew of the Enola Gay, which Tibbets flew in the atomic bombing of Hiroshima(AFP)
12 April 1946: Crew members of the Enola Gay proudly parade through New York on a Jeep in the first Army Day Parade since the end of the war(Getty)
September 1945: A Japanese soldier walks through a levelled area of the cityNational Archives
A patient's skin is burned in a pattern corresponding to the dark portions of a kimono worn at the time of the explosion(National Archives)
Patients at the Tokyo Imperial University Hospital display injuries suffered as a result of the atomic bomb that was dropped on Hiroshima(Getty)
1948: People look at the devastation in Hiroshima three years after the US dropped an atomic bomb on the city(AFP)