Founding (1945)
By 1 March 1945, 21 additional states had signed the Declaration by the United Nations. After months of planning, the UN Conference on International Organization opened in San Francisco on 25 April 1945. It was attended by 50 nations' governments and a number of non-governmental organizations.
The delegations of the Big Four chaired the plenary meetings. Previously, Churchill had urged Roosevelt to restore France to its status of a major power after the liberation of Paris in August 1944.
The drafting of the Charter of the United Nations was completed over the following two months, and it was signed on 26 June 1945 by the representatives of the 50 countries.
The UN officially came into existence on 24 October 1945, upon ratification of the Charter by the five permanent members of the Security Council: the United States, the United Kingdom, France, the Soviet Union and China — and by a majority of the other 46 nations.
The first meetings of the General Assembly, with 51 nations represented, and the Security Council took place in London beginning in January 1946. Debates began at once, covering topical issues such as the presence of Russian troops in Iranian Azerbaijan and British forces in Greece. British diplomat Gladwyn Jebb served as interim secretary-general.
The General Assembly selected New York City as the site for the headquarters of the UN. Construction began on 14 September 1948 and the facility was completed on 9 October 1952. The Norwegian Foreign Minister, Trygve Lie, was the first elected UN secretary-general.
The UN in 1945: founding members in light blue, protectorates and territories of the founding members in dark blue
The headquarters of the United Nations is on 17 to 18 acres of grounds in the Turtle Bay neighborhood of Midtown Manhattan in New York City.