February 20 is the fifty-first day of the year in the Gregorian calendar. 314 days (315 in leap years) remain in the year after this day.
1631 - German Protestant princes make an alliance with King Gustav II of Sweden, bringing Sweden into the Thirty Years' War (1618-1648).
1798 - French Marshal Louis Alexandre Bertie overthrows Pope Pius VI.
1809 - After a long siege, the French capture Zaragoza, rejecting Napoleon's brother Joseph as King of Spain.
1813 - Manuel Belgrano defeats Pia de Tristan's royalist army at the Battle of Salta.
1835 - An earthquake shakes the Chilean city of Concepcion.
1846 - Polish insurgents stage an uprising in the Free City of Krakow, which is suppressed by the Austrian Empire nine days later.
1860 - The first issue of "Danica", the most important literary magazine of Serbian romanticism, was published in Novi Sad, initiated and edited by Djordje Popovic.
1938 - British Foreign Secretary Anthony Eden resigns in protest of Prime Minister Neville Chamberlain's lenient policy toward German dictator Adolf Hitler.
1942 - A Japanese invasion of Timor, Portugal, and the island of Bali in Dutch East India.
1943 - A crack opens in a cornfield in the Mexican state of Michoacan, from which the volcano Parikutin erupted in nine years.
1962 - After successful suborbital manned flights, the United States launches the Mercury-Atlas 6 spacecraft into orbit around the Earth, with which the first American astronaut John Glenn orbits the Earth three times. The flight lasted four hours, 55 minutes and 23 seconds.
1967 - Indonesian President Ahmet Sukarno hands over all executive power to General Suharto, retaining only the "title" of president.
1979 - An eruption of Indonesia's Sinira volcano kills 175 people.
1985 - The sale of contraceptives is legalized in Ireland, despite fierce opposition from the Roman Catholic Church.
1986 - The USSR launches the first part of its Mir space station.
1986 - A religious conflict between Hindus, Muslims and Sikhs grips India, and a curfew is instituted in three Indian states.
1988 - The Nagorno-Karabakh Autonomous Region votes to secede from Azerbaijan and annex Armenia, sparking the Nagorno-Karabakh War.