On this day: August 20
Charles Darwin publishes his theory of evolution, the NFL is founded, Lou Gehrig belts his 23rd career grand slam and NASA heads for Mars, all on this day.
1775: The Spanish establish the Presidio San Augustin del Tucson in the town that will become Tucson, Ariz.
1775: The Spanish establish the Presidio San Augustin del Tucson in the town that will become Tucson, Ariz.
1833: Benjamin Harrison, the 23rd president of the United States, is born in North Bend, Ohio.
1858: Charles Darwin first publishes his theory of evolution through natural selection in The Journal of the Proceedings of the Linnean Society of London, alongside Alfred Russel Wallace's same theory.
1866: President Andrew Johnson formally declares the American Civil War over. The fighting had stopped months earlier.
1882: Peter Ilyich Tchaikovsky's 1812 Overture debuts in Moscow. The song is best known for its climactic volley of cannon fire, ringing chimes, and brass fanfare finale.
1920: The National Football League is founded at a car dealership in Canton, Ohio. It's originally called the American Professional Football Conference and features teams from the Ohio League.
1931: Boxing promoter Don King is born in Cleveland.
1935: Congressman Ron Paul, who ran for U.S. president in 1988, 2008 and 2012, is born in Pittsburgh.
1938: Lou Gehrig hits his 23rd career grand slam -- a record that still stands.
1940: British Prime Minister Winston Churchill makes the fourth of his famous wartime speeches, containing the line "Never was so much owed by so many to so few."
1942: Singer, songwriter and actor Isaac Hayes is born in Covington, Tenn.
1945: Tommy Brown of the Brooklyn Dodgers becomes the youngest player to hit a home run in a major league ball game. Brown was 17 years, eight months and 14 days old.
1948: Robert Plant, the former lead singer of Led Zeppelin, is born in West Bromwich, England.
1973: The Rolling Stones release "Angie." The song goes right to the top of the U.S. Billboard Hot 100 chart and reaches No. 5 on the UK singles chart.
1974: Actress Amy Adams ("Enchanted," "Doubt," "The Fighter") is born in Vicenza, Italy.
1975: NASA launches the Viking 1 planetary probe toward Mars. It becomes the first spacecraft to successfully land on Mars and perform its mission, and held the record for the longest Mars surface mission of six years and 116 days until that record was broken by the Opportunity Rover on May 19, 2010.
1977: NASA launches the Voyager 2 spacecraft to study the outer Solar System and eventually interstellar space.
1986: In Edmond, Okla., U.S. Postal employee Patrick Sherrill shoots 20 of his co-workers, killing 14 of them, and then commits suicide. The incident is credited with inspiring the American phrase "going postal." Pictured is a memorial at the site of the shooting.
1988: Firefighting continues in Yellowstone National Park, with the fires burning so much ground and producing such thick black smoke that the day is labeled "Black Saturday."
1992: Actress and singer Demi Lovato is born in Albuquerque, N.M.
1998: The United States launches cruise missile attacks against alleged al-Qaida camps in Afghanistan and a suspected chemical plant in Sudan in retaliation for the Aug. 7 bombings of American embassies in Kenya and Tanzania.
2007: Leona Helmsley, a hotel operator and real estate investor, dies from congestive heart failure at age 87 in Greenwich, Conn. She was known for her flamboyant personality and tyrannical behavior -- earning her the nickname "Queen of Mean" -- and was convicted of federal income tax evasion in 1989.
2012: Comedian/actress Phyllis Diller dies at the age of 95 in Los Angeles.
