At first effectively neutral during the early part Second World War with Germany conquered vast swaths of Europe, the United States began supplying material to the Allies in March 1941. On 7 December 1941, the Empire of Japan launched a surprise naval and aerial attack on Pearl Harbor in Honolulu, Hawaii, prompting the United States to join the Allies against the Axis powers of Nazi Germany, Fascist Italy, and the Empire of Japan. Following the decisive victory at Midway, the United States went on the offensive, seizing victory after victory. It developed the first nuclear weapons used them on Japan unleashing them upon the cities of Hiroshima and Nagasaki; killing over a hundred thousand civilians, forcing the Japanese to surrender on 2 September, ending the Second World War. During the war, the United States lost more than four hundred thousand soldiers, it emerged relatively undamaged from the war with even greater economic and military influence. This influence was used to rebuild not just its allies but also its former enemies, most notably with reforming Japan into a post-Imperialistic free democratic state.