After World War 2, the United Nations was established.
United Nations . The UN Charter was drafted at a conference between April -- June 1945 in San Francisco , and was signed on 26 June 1945 at the conclusion of the conference ; this charter took effect 24 October 1945 , and the UN began operation . World War II . With an invasion of the Japanese archipelago imminent , the possibility of additional atomic bombings , and the Soviet Union 's declaration of war on Japan and invasion of Manchuria , Japan surrendered on 15 August 1945 . Thus ended the war in Asia , cementing the total victory of the Allies .