October: Arthur C. Clarke puts forward the idea of a geosynchronous communications satellite in a Wireless World magazine article.
October 1- 15: Operation Backfire: Three A4 rockets are launched near Cuxhaven in order to show Allied forces the rocket with liquid fuel.
October 2: George Albert Smith becomes president of the Church of Jesus Christ of Latter-day Saints
October 3-10: The Detroit Tigers win the World Series against the Chicago Cubs; the Cubs have not returned to the World Series since.
October 4: The Partizan Belgrade sports society is founded in Belgrade, Serbia.
October 5: A strike by the Set Decorator's Union in Hollywood results in a riot.
October 9: Pierre Laval is sentenced to death for collaboration with the Nazis.
October 14: Czechoslovakia: A new provisional national assembly is elected.
October 15: Pierre Laval, the former premier of Vichy France, is shot to death by a firing squad for treason against France.
October 15-21: The Fifth Pan-African Congress is held in Manchester, United Kingdom.
October 16: Food and Agriculture Organization established as a specialized agency of the United Nations.
October 17: A massive number of people, headed for CGT, gather in the Plaza de Mayo in Argentina to demand Juan Perón's release. This is known to the Peronists as the Día de la lealtad (Loyalty Day) and considered the founding day of Peronism.
October 18: Isaías Medina Angarita, president of Venezuela, is overthrown by a military coup.
October 19: Members of the Indonesian People's Army attack Anglo-Dutch forces in Indonesia.
October 20: Mongolians vote for independence from China.
October 21: Women's suffrage: Women are allowed to vote in France for the first time.
October 22: Romulo Betancourt is named provisional president of Venezuela.
October 23: Jackie Robinson signs a contract with the Montreal Royals baseball team.
October 24: The United Nations is founded by ratification of its Charter, by 29 nations. - International Court of Justice ("World Court") established by the United Nations Charter. - The Norwegian Nazi leader Vidkun Quisling is shot to death by a firing squad for treason against Norway.
October 25: Getulio Vargas is deposed as president in Brazil. José Linhares is named as temporary president.
October 27: Indonesian separatists riot and fight Dutch and British security forces.
October 29: Getúlio Vargas resigns as the president of Brazil. - At Gimbels Department Store in New York City, the first ballpoint pens go on sale at $12.50 each.
October 30: The undivided country of India joins the United Nations. Pakistan is formed and joins later. (source: Wikipedia)