During the final stages of World War II in 1945, the UnitedStates conducted two atomic bombings against the cities of Hiroshima and Nagasaki in Japan. These two events are the only use of nuclear weapons in war to date. Following a firebombing campaign that destroyed manyJapanese cities, the Allies prepared for a costly invasion of Japan. The war in Europe ended when Nazi Germany signed its instrument of surrender on 8 May, but the Pacific War continued. Together with the United Kingdom and the Republic ofChina, the United States called for a surrender of Japan in the Potsdam Declaration on 26 July 1945, threateningJapan with "prompt and utter destruction". The Japanesegovernment ignored this ultimatum, and the United States deployed two nuclear weapons developed by theManhattan Project. American soldiers dropped Little Boy on the city of Hiroshima on 6 August 1945, followed by Fat Man over Nagasaki on 9 August.