The United States, officially neutral during the early stages of World War II, began supplying supplies to the Allies in March 1941, through the Lend-Lease program. On December 7, 1941, the country joined the Allies fight against the Axis Powers, after the Japanese attack on Pearl Harbor. World War II boosted the economy by providing investment capital and jobs, making many women enter the labor market. Of the significant fighters, the United States was the only nation to be enriched by war. The discussions at Bretton Woods and Yalta created a new system of international organization that placed the country and the Soviet Union at the heart of world affairs. In 1945, when the end of the Second World War in Europe came, an international gathering held in San Francisco drafted the Charter of the United Nations, which came into force after the war. Having developed the first nuclear weapon, the government decided to use it in the Japanese cities of Hiroshima and Nagasaki in August of that same year. Japan gave up on September 2, ending the war.