| 121051 | October 23 | Event | 1870 – Franco-Prussian War: The Siege of Metz concludes with a decisive Prussian victory. |
| 121052 | October 23 | Event | 1906 – Alberto Santos-Dumont flies an airplane in the first heavier-than-air flight in Europe at Champs de Bagatelle, Paris, France. |
| 121053 | October 23 | Event | 1911 – First use of aircraft in war: Italo-Turkish War: An Italian pilot takes off from Libya to observe Turkish army lines. |
| 121054 | October 23 | Event | 1912 – First Balkan War: The Battle of Kumanovo between the Serbian and Ottoman armies begins. |
| 121055 | October 23 | Event | 1915 – Women's suffrage: In New York City, 25,000–33,000 women march on Fifth Avenue to advocate their right to vote. |
| 121056 | October 23 | Event | 1917 – Lenin calls for the October Revolution. |
| 121057 | October 23 | Event | 1929 – Great Depression: After a steady decline in stock market prices since a peak in September, the New York Stock Exchange begins to show signs of panic. |
| 121058 | October 23 | Event | 1935 – Dutch Schultz, Abe Landau, Otto Berman, and Bernard "Lulu" Rosencrantz are fatally shot at a saloon in Newark, New Jersey in what will become known as The Chophouse Massacre. |
| 121059 | October 23 | Event | 1939 – The Japanese Mitsubishi G4M twin-engine "Betty" Bomber makes its maiden flight. |
| 121060 | October 23 | Event | 1941 – World War II: Field Marshal Georgy Zhukov takes command of Red Army operations to prevent the further advance into Russia of German forces and to prevent the Wehrmacht from capturing Moscow. |
| 121061 | October 23 | Event | 1942 – World War II: Second Battle of El Alamein: At El Alamein in northern Egypt, the British Eighth Army under Field Marshal Montgomery begins a critical offensive to expel the Axis armies from Egypt. |
| 121062 | October 23 | Event | 1942 – All 12 passengers and crewmen aboard an American Airlines DC-3 airliner are killed when it is struck by a U.S. Army Air Forces bomber near Palm Springs, California. Amongst the victims is award-winning composer and songwriter Ralph Rainger ("Thanks |
| 121063 | October 23 | Event | 1942 – World War II: The Battle for Henderson Field begins during the Guadalcanal Campaign and ends on October 26. |
| 121064 | October 23 | Event | 1944 – World War II: Battle of Leyte Gulf: The largest naval battle in history begins in the Philippines. |
| 121065 | October 23 | Event | 1946 – The United Nations General Assembly convenes for the first time, at an auditorium in Flushing, Queens, New York City. |
| 121066 | October 23 | Event | 1955 – Prime Minister Ngô Đình Diệm defeats former emperor Bảo Đại in a referendum and founds the Republic of Vietnam. |
| 121067 | October 23 | Event | 1956 – Thousands of Hungarians protest against the government and Soviet occupation. (The Hungarian Revolution is crushed on November 4). |
| 121068 | October 23 | Event | 1958 – The Springhill Mine bump: An underground earthquake traps 174 miners in the No. 2 colliery at Springhill, Nova Scotia, the deepest coal mine in North America at the time. By November 1, rescuers from around the world had dug out 100 of the victims, |
| 121069 | October 23 | Event | 1958 – The Smurfs, a fictional race of blue dwarves, later popularized in a Hanna-Barbera animated cartoon series, appear for the first time in the story La flute à six schtroumpfs, a Johan and Peewit adventure by Peyo, which is serialized in the weekly S |
| 121070 | October 23 | Event | 1965 – Vietnam War: The 1st Cavalry Division (United States) (Airmobile), in conjunction with South Vietnamese forces, launches a new operation seeking to destroy North Vietnamese forces in Pleiku in the II Corps Tactical Zone (the Central Highlands). |
| 121071 | October 23 | Event | 1970 – Gary Gabelich sets a land speed record in a rocket-powered automobile called the Blue Flame, fueled with natural gas. |
| 121072 | October 23 | Event | 1972 – Operation Linebacker, a US bombing campaign against North Vietnam in response to its Easter Offensive, ends after five months. |
| 121073 | October 23 | Event | 1973 – The Watergate scandal: US President Richard M. Nixon agrees to turn over subpoenaed audio tapes of his Oval Office conversations. |
| 121074 | October 23 | Event | 1973 – A United Nations sanctioned cease-fire officially ends the Yom Kippur War between Israel and Syria. |
| 121075 | October 23 | Event | 1983 – Lebanese Civil War: The U.S. Marines barracks in Beirut is hit by a truck bomb, killing 241 U.S. military personnel. A French army barracks in Lebanon is also hit that same morning, killing 58 troops. |
| 121076 | October 23 | Event | 1989 – The Hungarian Republic is officially declared by president Mátyás Szűrös, replacing the communist Hungarian People's Republic. |
| 121077 | October 23 | Event | 1989 – Bankruptcy of Wärtsilä Marine the biggest bankruptcy in the Nordic countries until then. |
| 121078 | October 23 | Event | 1993 – The Troubles: A Provisional IRA bomb prematurely detonates in the Shankill area of Belfast, killing the bomber and nine civilians. Ulster loyalists retaliate a week later with the Greysteel massacre. |
| 121079 | October 23 | Event | 1995 – Yolanda Saldívar is found guilty of first-degree murder in the shooting death of popular Latin singer Selena. Three days later, Saldívar was sentenced to life in prison, eligible for parole in 2025 |
| 121080 | October 23 | Event | 1998 – Israeli–Palestinian conflict: Israeli Prime Minister Benjamin Netanyahu and Palestinian Chairman Yasser Arafat reach a "land for peace" agreement. |