20 April Events

April 20 is the 110th day of the year (111th in leap years) in the Gregorian calendar. There are 255 days remaining until the end of the year.

Events

1303 – The Sapienza University of Rome is instituted by Pope Boniface VIII.
1453 – Three Genoese galleys and a Byzantine blockade runner fight their way through an Ottoman blockading fleet a few weeks before the fall of Constantinople.
1534 – Jacques Cartier begins his first voyage to what is today the east coast of Canada, Newfoundland and Labrador.
1535 – The sun dog phenomenon observed over Stockholm and depicted in the famous painting Vädersolstavlan.
1653 – Oliver Cromwell dissolves the Rump Parliament.
1657 – Admiral Robert Blake destroys a Spanish silver fleet under heavy fire at the Battle of Santa Cruz de Tenerife.
1657 – Freedom of religion is granted to the Jews of New Amsterdam (later New York City).
1689 – Deposed monarch James II of England lays siege to Derry.
1752 – Start of Konbaung–Hanthawaddy War, a new phase in the Burmese Civil War (1740–57).
1770 – The Georgian king, Erekle II, abandoned by his Russian ally Count Totleben, wins a victory over Ottoman forces at Aspindza.
1775 – American Revolutionary War: The Siege of Boston begins, following the battles at Lexington and Concord.
1789 – George Washington arrives at Grays Ferry, Philadelphia while en route to Manhattan for his inauguration.
1792 – France declares war against the "King of Hungary and Bohemia", the beginning of French Revolutionary Wars.
1800 – The Septinsular Republic is established.
1809 – Two Austrian army corps in Bavaria are defeated by a First French Empire army led by Napoleon at the Battle of Abensberg on the second day of a four-day campaign that ended in a French victory.
1810 – The Governor of Caracas, Venezuela declares independence from Spain.
1818 – The case of Ashford v Thornton ends, with Abraham Thornton allowed to go free rather than face a retrial for murder, after his demand for trial by battle is upheld.
1828 – René Caillié becomes the second non-Muslim to enter (and the first to return from) Timbuktu, following Major Gordon Laing.
1836 – U.S. Congress passes an act creating the Wisconsin Territory.
1861 – American Civil War: Robert E. Lee resigns his commission in the United States Army in order to command the forces of the state of Virginia.
1862 – Louis Pasteur and Claude Bernard complete the experiment falsifying the theory of spontaneous generation.
1865 – Astronomer Angelo Secchi demonstrates the Secchi disk, which measures water clarity, aboard Pope Pius IX's yacht, the L'Immaculata Concezion.
1876 – The April Uprising begins. Its suppression shocks European opinion, and Bulgarian independence becomes a condition for ending the Russo-Turkish War.
1884 – Pope Leo XIII publishes the encyclical Humanum genus.
1898 – U.S. President William McKinley signed a joint resolution to Congress for declaration of War against Spain, beginning the Spanish–American War.
1902 – Pierre and Marie Curie refine radium chloride.
1908 – Opening day of competition in the New South Wales Rugby League.
1912 – Opening day for baseball's Tiger Stadium in Detroit, and Fenway Park in Boston.
1914 – Nineteen men, women, and children die in the Ludlow Massacre during a Colorado coal-miner's strike.
1916 – The Chicago Cubs play their first game at Weeghman Park (currently Wrigley Field), defeating the Cincinnati Reds 7–6 in 11 innings.
1918 – Manfred von Richthofen, a.k.a. The Red Baron, shoots down his 79th and 80th victims, his final victories before his death the following day.
1922 – The Soviet government creates South Ossetian Autonomous Oblast within Georgian SSR.
1945 – World War II: U.S. troops capture Leipzig, Germany, only to later cede the city to the Soviet Union.
1945 – World War II: Führerbunker: Adolf Hitler makes his last trip to the surface to award Iron Crosses to boy soldiers of the Hitler Youth.
1945 – Twenty Jewish children used in medical experiments at Neuengamme are killed in the basement of the Bullenhuser Damm school.
1946 – The League of Nations officially dissolves, giving most of its power to the United Nations.
1961 – Cold War: Failure of the Bay of Pigs Invasion of US-backed Cuban exiles against Cuba.
1968 – English politician Enoch Powell makes his controversial Rivers of Blood speech.
1972 – Apollo program: Apollo 16, commanded by John Young, lands on the moon.
1999 – Columbine High School massacre: Eric Harris and Dylan Klebold killed 13 people and injured 24 others before committing suicide at Columbine High School in Columbine, Colorado.
2007 – Johnson Space Center shooting: William Phillips with a handgun barricades himself in NASA's Johnson Space Center in Houston, Texas before killing a male hostage and himself.
2008 – Danica Patrick wins the Indy Japan 300 becoming the first female driver in history to win an Indy car race.
2010 – The Deepwater Horizon drilling rig explodes in the Gulf of Mexico, killing eleven workers and beginning an oil spill that would last six months.
2012 – One hundred twenty-seven people are killed when a plane crashes in a residential area near the Benazir Bhutto International Airport near Islamabad, Pakistan.
2013 – A 6.6-magnitude earthquake strikes Lushan County, Ya'an, in China's Sichuan province, killing more than 150 people and injuring thousands.
2015 – Ten people are killed in a bomb attack on a convoy carrying food supplies to a United Nations compound in Garowe in the Somali region of Puntland.

Source: wikipedia