Final Stage Of World War II

During the final stage of World War II, the United States dropped nuclear weapons on the Japanese cities of Hiroshima and Nagasaki on August 6 and 9, 1945, respectively. The United States had dropped the bombs with the consent of the United Kingdom as outlined in the Quebec Agreement. The two bombings, which killed at least 129,000 people, remain the only use of nuclear weapons for warfare in history. In the final year of the war, the Allies prepared for what was anticipated to be a very costly invasion of the Japanese mainland. This was preceded by a U.S. conventional and firebombing campaign that destroyed 67 Japanese cities. The war in Europe had concluded when Nazi Germany signed its instrument of surrender on May 8, 1945. The Japanese, facing the same fate, refused to accept the Allies' demands for unconditional surrender and the Pacific War continued. The Allies called for the unconditional surrender of the Imperial Japanese armed forces in the Potsdam Declaration on July 26, 1945—the alternative being "prompt and utter destruction". The Japanese response to this ultimatum was to ignore it.

By August 1945, the Allies' Manhattan Project had produced two types of atomic bomb, and the 509th Composite Group of the United States Army Air Forces was equipped with the specialized Silverplate version of the Boeing B-29 Superfortress that could deliver them from Tinian in the Mariana Islands. Orders for atomic bombs to be used on four Japanese cities were issued on July 25. On August 6, the U.S. dropped a uranium gun-type bomb on Hiroshima, and American President Harry S. Truman called for Japan's surrender, warning it to "expect a rain of ruin from the air, the like of which has never been seen on this earth." Three days later, on August 9, a plutonium implosion-type bomb was dropped on Nagasaki.