On July 26, 1945, the United States called for the unconditional surrender of Japan under threat of "prompt and utter destruction."
Two days later, newspapers reported that the Japanese government had officially rejected the proposed ultimatum. Soon after, the world's first atomic bomb was dropped over the Japanese city of Hiroshima, killing an estimated 70,000 people instantly upon detonation.
Three days later, a second atomic bomb was dropped, on Nagasaki. With the effects of radiation, the total number of victims is thought to be approximately 340,000 people. On Aug. 15, 1945, the surrender of Japan was publicly announced and World War II was brought to an end.
Aug. 2, 1939: Albert Einstein writes to President Franklin D. Roosevelt, warning of the possibility of an atomic bomb.
July 16, 1945: America's first atomic bomb is tested at the White Sands Proving Ground.
July 1945: The decision is ultimately made to use the atomic bomb against Japan.
August 5: The crew is briefed prior to the flight of the Enola Gay.
The war department issued shoulder patches to approximately 3,500 Army officers and men assigned to work on the atomic bomb (left). Tibbets, pilot of the Enola Gay, waves from his cockpit before takeoff (right).
Aug. 6, 1945: The atomic bomb is detonated over Hiroshima.
Photo from the U.S. Army Signal Corps showing the devastation left after the first atomic bomb was droppped on Hiroshima.
For those who survived, the damage from the bomb's intense heat and radiation caused lasting damage.
A mother tends her injured child, a victim of the atomic bomb blast at Hiroshima.
A man whose back has been totally burned during the atomic bomb dropped by the U.S. on Hiroshima (left). Two brothers who survived the atomic bombing of Hiroshima (right).