The Japanese attacked Pearl Harbor in 1941, hoping to destroy the US Navy and force American acceptance of Japanese dominance in the Pacific. However, the attack united Americans and convinced them to enter the war against Japan. By 1942, the Japanese controlled much of Southeast Asia and the Pacific, but Allied victories at the Battles of the Coral Sea and Midway turned the tide. US forces led by MacArthur began moving through the Pacific islands toward Japan in 1942. Atomic bombs were dropped on Hiroshima and Nagasaki in 1945, destroying the cities and killing thousands, after which Japan surrendered, ending World War II.