The USA was brought into World War II after they had been suddenly attacked by Japan on December 7, 1941. The entire Pacific and southeast Asia became a new battleground. The attack on Hawaii was supposed to prevent the Americans from interfering with the Japanese conquest. Although the American industry was more developed than the Japanese, the Japanese planned to conclude the War before the Americans could get a chance to recover. The Japanese pursued their detailed plan and continued their conquests towards the South, and they managed to occupy the Philippines, Indonesia and Malaya. They were successful in getting hold of important raw materials needed for waging a war, and later they occupied also the central part of the Pacific. They came all the way to Australia where they were stopped. In the mid-1942, the Americans succeeded to resist the Japanese by persistently bringing reinforcements, war funding and other ships. The Pacific was a battlefield for small armies, but also for big fleets. Battles had been taking place for months and years, and the Americans started to gain predominance. They wanted to force the Japanese to an unconditional surrender, but they failed. That was the case all the way up to the 1945, when the Americans dropped two atomic bombs on Japanese cities Hiroshima and Nagasaki. The atomic bomb induced a mental and physical attack which was enough for the Japanese to decide to sign the unconditional capitulation and surrender. The act of surrender was signed on September 2, 1945, which also meant the end of World War II.