1976: The ferry George Prince is struck by a ship while crossing the Mississippi River between Destrehan and Luling, Louisiana. Seventy-eight passengers and crew die, and only 18 people aboard the ferry survive.
1962: People's Republic of China launches simultaneous offensives in Ladakh and across the McMahon Line, igniting the Sino-Indian War.
1961: The Soviet Union performs the first armed test of a submarine-launched ballistic missile, launching an R-13 from a Golf-class submarine.
1952: Governor Evelyn Baring declares a state of emergency in Kenya and begins arresting hundreds of suspected leaders of the Mau Mau Uprising, including Jomo Kenyatta, the future first President of Kenya.
1947: The United States of America and the Islamic Republic of Pakistan establish diplomatic relations for the first time.
1947: The House Un-American Activities Committee begins its investigation into Communist infiltration of the cinema of the United States, resulting in a blacklist that prevents some from working in the industry for years.
1946: Government of the Democratic Republic of Vietnam decides that October 20 is Vietnam Women's Day.
1944: American general Douglas MacArthur fulfills his promise to return to the Philippines when he commands an Allied assault on the islands, reclaiming them from the Japanese during the Second World War.
1944: Liquefied natural gas leaks from storage tanks in Cleveland and then explodes; the explosion and resulting fire level 30 blocks and kill 130.
1873: Yale, Princeton, Columbia, and Rutgers universities draft the first code of American football rules.
1827: In the Battle of Navarino, a combined Turkish and Egyptian fleet is defeated by British, French, and Russian naval forces in the last significant battle fought with wooden sailing ships.
1818: The Convention of 1818 is signed between the United States and the United Kingdom, which settles the Canada-United States border on the 49th parallel for most of its length.
1548: The city of Nuestra Señora de La Paz (Our Lady of Peace) is founded by Alonso de Mendoza by appointment of the king of Spain and Holy Roman Emperor, Charles V.