United Nations 1945, 50 governments met in San Francisco for a conference and started drafting the UN Charter, which was adopted on 25 June 1945 in the San Francisco Opera House, and signed on 26 June 1945 in the Herbst Theatre auditorium in the Veterans War Memorial Building. This charter took effect on 24 October 1945, when the UN began operation. The UN's mission to preserve world peace was complicated in its early decades during the Cold War between the United States and Soviet Union and their respective allies. Its missions have consisted primarily of unarmed military observers and lightly armed troops
International Civil Aviation Organization convention, held in London in 1912 allocated the first radio callsigns for use by aircraft. ICAN continued to operate until 1945. Fifty-two countries signed the Chicago Convention on International Civil Aviation, also known as the Chicago Convention, in Chicago, Illinois, on 7 December 1944. Under its terms, a Provisional International Civil Aviation Organization (PICAO) was to be established, to be replaced in turn by a permanent organization when 26 countries ratified the convention. Accordingly, PICAO began operating on 6 June 1945, replacing ICAN. The 26th country ratified the Convention on 5 March 1947 and, consequently PICAO was disestablished on 4