20th of August

It is the 232nd day of the year with only 133 days remaining until the end of the year.

1775 - The Spanish establish a presidio, more commonly referred to as a fort, in the town that became Tucson, Arizona.

1794 - American troops force a confederacy of Shawnee, Mingo, Delaware, Wyandot, Miami, Ottawa, Chippewa, and Potawatomi warriors into a disorganized retreat during the Battle of Fallen Timbers.

1804 - The Lewis and Clark Expedition, suffers its only death when Sergeant Charles Floyd dies, apparently from acute appendicitis.

1858 - Charles Darwin first publishes his theory of evolution through natural selection in The Journal of the Proceedings of the Linnean Society of London.

1866 - President Andrew Johnson makes a formal declaration that the American Civil War is over.

1882 - Peter Ilyich Tchaikovsky's 1812 Overture debuts in Moscow.

1910 - The Great Fire of 1910 occurred in northeast Washington, northern Idaho, and western Montana, scorching approximately 3 million acres, nearly 12,000 square kilometers.

1920 - The first commercial radio station, 8MK or WWJ, begins operations in Detroit, Michigan.

1920 - The National Football League is founded in the United States.

1931 - American boxing promoter, known for his hairstyle and flamboyant personality, Don King is born.

1938 - Lou Gehrig hits his 23rd career grand slam - a record that still stands to this day.

1944 - 168 captured Allied airmen, including Phil Lamason, accused by the Gestapo of being "terror fliers," arrive at the Buchenwald concentration camp.

1948 -  Robert Plant, English rock singer and songwriter of Led Zeppelin is born.

1960 - Senegal breaks from the Mali federation, officially declaring its independence.

1975 - The National Aeronautical and Space Administration launches the Viking 1 planetary probe into space, bound for Mars.

1988 - A cease-fire is agreed upon after almost eight years of war, between both Iran and Iraq.

1991 - More than 100,000 people rally outside around the Soviet Union's parliament building protesting the coup aiming to depose President Mikhail Gorbachev.

1991 - Estonia, annexed by the USSR in 1940, issues a decision on the re-establishment of independence on the basis of historical continuity of her pre-World War II statehood.

2008 - Ed "Too Tall" Freeman, a United States Army helicopter pilot who received the Medal of Honor, for his actions in the Battle of Ia Drang during the Vietnam War, passes away at the age of 80.