November 20th.

* 284 - Diocletian was chosen as Roman Emperor.
* 762 - Bvg|, Khan of the Uyghurs, conquers Lo-Yang, capital of the Chinese Empire.
* 1194 - Palermo is conquered by Emperor Henry VI.
* 1407 - A truce between John the Fearless, Duke of Burgundy and Louis of Valois, Duke of Orlians is agreed under the auspices of John, Duke of Berry. Orlians would be assassinated three days later by Burgundy.
* 1695 - Zumbi, the last of the leaders of Quilombo dos Palmares in early Brazil, is executed.
* 1700 - Great Northern War: Battle of Narva - King Charles XII of Sweden defeats the army of Tsar Peter the Great at Narva.
* 1910 - Mexican Revolution: Francisco I. Madero issues the Plan de San Luis Potosi, denouncing President Porfirio Dmaz, calling for a revolution to overthrow the government of Mexico, effectively starting the Mexican Revolution.
* 1917 - World War I: Battle of Cambrai begins - British forces make early progress in an attack on German positions but are later pushed back.
* 1917 - Ukraine is declared a republic.
* 1923 - Rentenmark replaces the Papiermark as the official currency of Germany at the exchange rate of one Rentenmark to One Trillion (One Billion on the long scale) Papiermark
* 1940 - World War II: Hungary, Romania and Slovakia join the Axis Powers.
* 1943 - World War II: Battle of Tarawa (Operation Galvanic) begins - United States Marines land on Tarawa Atoll in the Gilbert Islands and suffer heavy fire from Japanese shore guns and machine guns.
* 1945 - Nuremberg Trials: Trials against 24 Nazi war criminals start at the Palace of Justice at Nuremberg.
* 1952 - Slansk} trials - a series of Stalinist and anti-Semitic show trials in Czechoslovakia.
* 1962 - Cuban Missile Crisis ends: In response to the Soviet Union agreeing to remove its missiles from Cuba, U.S. President John F. Kennedy ends the quarantine of the Caribbean nation.
* 1968 - Vietnam War: Eleven men comprising a Long Range Patrol team from F Company, 58th Infantry, 101st Airborne are surrounded and nearly wiped out by North Vietnamese army regulars from the 4th and 5th Regiment. The seven wounded survivors are rescued after several hours by an impromptu force made of other men from their unit.
* 1969 - Vietnam War: The Cleveland Plain Dealer publishes explicit photographs of dead villagers from the My Lai massacre in Vietnam.
* 1974 - The United States Department of Justice files its final anti-trust suit against AT&T. This suit later leads to the break up of AT&T and its Bell System.
* 1975 - Francisco Franco, Caudillo of Spain dies after 36 years in power.
* 1979 - Grand Mosque Seizure: About 200 Sunni Muslims revolt in Saudi Arabia at the site of the Kaaba in Mecca during the pilgrimage and take about 6000 hostages in the Kaaba. The Saudi government received help from French special forces to put down the uprising.
* 1989 - Velvet Revolution: The number of protesters assembled in Prague, Czechoslovakia swells from 200,000 the day before to an estimated half-million.
* 1994 - The Angolan government and UNITA rebels sign the Lusaka Protocol in Zambia, ending 19 years of civil war (localized fighting resumed the next year).
* 1998 - A court in Taliban-controlled Afghanistan declares accused terrorist Osama bin Laden "a man without a sin" in regard to the 1998 U.S. embassy bombings in Kenya and Tanzania.