Hiroshima and Nagasaki Bombings

During the final stages of World War II in 1945, the United States conducted two atomic bombings against Japan in the cities of Hiroshima and Nagasaki.

The bombs killed as many as 140,000 people in Hiroshima and 80,000 in Nagasaki by the end of 1945, with roughly half of those deaths occurring on the days of the bombings. Amongst these, 15–20% died from injuries or the combined effects of flash burns, trauma, and radiationburns, compounded by illness, malnutrition and radiation sickness. Since then, more have died from leukemia (231 observed) and solid cancers (334 observed) attributed to exposure to radiation released by the bombs. In both cities, most of the dead were civilians

The first bomb dropped on Hiroshima, one of the chief supply depots for the Japanese army, was more than 2,000 times more powerful than the largest bomb used to date. The bomb was dropped from an American B-29 Superfortress, known as Enola Gay. The plane's crew says they saw a column of smoke rising and intense fires springing up

The atomic bomb heralded the "harnessing of the basic power of the universe". It also marked a victory over the Germans in the race to be first to develop a weapon using atomic energy.

On July 26, allied leaders issued the Potsdam Declaration outlining terms of surrender for Japan. It was presented as an ultimatum and stated that without a surrender, the Allies would attack Japan, resulting in "the inevitable and complete destruction of the Japanese armed forces and just as inevitably the utter devastation of the Japanese homeland". The atomic bomb was not mentioned in the communique. On July 28, Japanese papers reported that the declaration had been rejected by the Japanese government

After the bombings, The Japanese government still did not react to the Potsdam Declaration. Emperor Hirohito, the government, and the war council were considering four conditions for surrender: the preservation of the kokutai (Imperial institution and national polity), assumption by the Imperial Headquarters of responsibility for disarmament and demobilization, no occupation of the Japanese Home Islands, Korea, or Formosa, and delegation of the punishment of war criminals to the Japanese government.

Six days after the detonation over Nagasaki, on August 15, Japan announced its surrender to the Allied Powers, signing the Instrument of Surrender on September 2, officially ending the Pacific War and therefore World War II. The bombings led, in part, to post-war Japan adopting Three Non-Nuclear Principles, forbidding the nation from nuclear armament.