THIS DAY IN HISTORY ― JUNE 20

June 20 is the 171st day of the year (172nd in leap years) in the Gregorian calendar. There are 194 days remaining until the end of the year. 

NATIONAL AMERICAN EAGLE DAY 

451 – Battle of Chalons (Battle of the Catalaunian Plains): Flavius Aetius' battles Attila the Hun. After the battle, which was inconclusive, Attila retreats, causing the Romans to interpret it as a victory.

1756 – A British garrison is imprisoned in the Black Hole of Calcutta.

1782 – The U.S. Congress adopts the Great Seal of the United States. The obverse of the great seal is used as the national coat of arms of the United States. It is officially used on documents such as United States passports, military insignia,embassy placards, and various flags. As a coat of arms, the design has official colors; the physical Great Seal itself, as affixed to paper, is monochrome.\

1819 – The U.S. vessel SS Savannah arrives at Liverpool, United Kingdom. It is the first steam-propelled vessel to cross the Atlantic, although most of the journey is made under sail.

1837 – Queen Victoria succeeds to the British throne. Before Queen Elizabeth II she was the longest reigning British monarch.

1840 – American painter and inventor Samuel Morse receives the patent for the telegraph.

1877 – Sottish-born scientist, inventor, engineer Alexander Graham Bell installs the world's first commercial telephone service in Hamilton, Ontario, Canada.

1893 – Lizzie Andrew Borden is acquitted of the murders of her father and stepmother in Fall River, Massachusetts.

1895 – The Kiel Canal, crossing the base of the Jutland peninsula and the busiest artificial waterway in the world, is officially opened.  It links the North Sea at Brunsbüttel to the Baltic Sea at Kiel-Holtenau. An average of 250 nautical miles (460 km) is saved by using the Kiel Canal instead of going around the Jutland Peninsula. This not only saves time but also avoids potentially dangerous storm-prone seas.

1900 – The Boxer Rebellion: The Imperial Chinese Army begins a 55-day siege of the Legation Quarter in Beijing, China.

1900 – Baron Eduard Toll, leader of the Russian Polar Expedition of 1900, departs Saint Petersburg, Russia on the explorer ship Zarya, never to return. 

1940 – World War II: Italy begins an unsuccessful invasion of France.

1942 – The Holocaust: Kazimierz Piechowski and three others, dressed as members of the SS-Totenkopfverbände, steal an SS staff car and escape from the Auschwitz concentration camp.

1943 – The Detroit race riot breaks out and continues for three more days before thousands of Federal troops were called in to establish control. It occurred in a period of dramatic population increase associated with the military buildup as Detroit's auto industry was converted to the war effort; nearly 400,000 migrants, both African American and European American, came from the Southeastern United States from 1941 to 1943 and were competing for jobs and housing in an already crowded city, both between each other and with foreign immigrants.

1945 – The United States Secretary of State approves the transfer of Wernher von Braun and his team of Nazi rocket scientists to America.

1959 – A rare June hurricane strikes Canada's Gulf of St. Lawrence killing 35.

1963 – The so-called "red telephone" link is established between the Soviet Union and the United States following the Cuban Missile Crisis.

1972 – Watergate scandal: An 18½-minute gap appears in the tape recording of the conversations between U.S. President Richard Nixon and his advisers regarding the recent arrests of his operatives while breaking into the Watergate complex.

1973 – Ezeiza massacre in Buenos Aires, Argentina. Snipers fire upon left-wing Peronists. At least 13 are killed and more than 300 are injured.

1975 – The film Jaws is released in the United States, becoming the highest-grossing film of that time and starting the trend of films known as "summer blockbusters".

1990 – The 7.4 Mw Manjil–Rudbar earthquake affects northern Iran with a maximum Mercalli intensity of X (Extreme), killing 35,000–50,000, and injuring 60,000–105,000.

1991 – The German Bundestag votes to move the capital from Bonn back to Berlin.

2001 – Andrea Yates, in an attempt to save her young children from Satan, drowns all five of them in a bathtub in Houston, Texas. Her case placed theM'Naghten Rules, along with the Irresistible Impulse Test, a legal test for sanity, under close public scrutiny in the United States. She was convicted of capital murder. After the guilty verdict, but before sentencing, the State abandoned its request for the death penalty in light of false testimony by one of its expert psychiatric witnesses. She was sentenced to life in prison with the possibility of parole after 40 years. The verdict was overturned on appeal.

2003 – The Wikimedia Foundation is founded in St. Petersburg, Florida.

BORN TODAY

1469 – Gian Galeazzo Sforza, Duke of Milan (d. 1494)

1819 – Jacques Offenbach, German-French cellist and composer, Orpheus in the Underworld "can-can" (d. 1880)
1858 – Charles W. Chesnutt, African-American novelist and short story writer (d. 1932)

1861 – Frederick Gowland Hopkins, English biochemist and academic, Nobel Prize laureate for discovering vitamins and Tryptophan (d. 1947)

1884 – Mary R. Calvert, American astronomer and author (d. 1974)

1905 – Lillian Hellman, American playwright and screenwriter (d. 1984)

1923 – Peter Gay (born Peter Joachim Fröhlich), German-American historian, author, and academic (d. 2015)

1941 – Ulf Merbold, German physicist and astronaut

From Wikipedia and Google (images), ex as noted.