1139 – The Second Lateran Council opened in Rome.
1534 – Jacques Cartier, a French explorer, set sail from St. Malo to explore the North American coastline.
1653 – In England, Oliver Cromwell expelled the Long Parliament for trying to pass the Perpetuation Bill that would have kept Parliament in the hands of only a few members.
1657 – English Admiral Robert Blake fought his last battle when he destroyed the Spanish fleet in Santa Cruz Bay.
1689 – The siege of Londonderry began. Supporters of James II attacked the city.
1769 – Ottawa Chief Pontiac was murdered by an Illinois Indian in Cahokia.
1775 – American troops began the siege of British-held Boston.
1792 – France declared war on Austria, Prussia, and Sardinia. It was the start of the French Revolutionary wars.
1809 – Napoleon defeated Austria at Battle of Abensberg, Bavaria.
1832 – Hot Springs National Park was established by an act of the U.S. Congress. It was the first national park in the U.S.
1836 – The U.S. territory of Wisconsin was created by the U.S. Congress.
1837 – Erastus B. Bigelow was granted a patent for his power loom.
1841 – In Philadelphia, PA, Edgar Allen Poe’s first detective story, “The Murders in the Rue Morgue,” was published in Graham’s Magazine.
1861 – Robert E. Lee resigned from U.S. Army.
1865 – Safety matches were first advertised.
1879 – First mobile home (horse drawn) was used in a journey from London to Cyprus.
1902 – Scientists Marie and Pierre Curie isolated the radioactive element radium.
1912 – Fenway Park opened as the home of the Boston Red Sox.
1916 – Sir Roger Casement landed in Ireland to incite rebellion against the British. Casement, a British diplomat, was captured within hours and was hanged for high treason on August 3.
1916 – Chicago’s Wrigley Field held its first Cubs game with the first National League game at the ballpark. The Cubs beat the Cincinnati Reds 7-6 in 11 innings.
1919 – The Polish Army captured Vilno, Lithuania from the Soviets.
1940 – The First electron microscope was demonstrated by RCA.
1942 – Pierre Laval, the premier of Vichy France, in a radio broadcast, establishes a policy of “true reconciliation with Germany.”
1945 – Soviet troops began their attack on Berlin.
1945 – During World War II, Allied forces took control of the German cities of Nuremberg and Stuttgart.
1953 – Operation Little Switch began in Korea. It was the exchange of sick and wounded prisoners of war. Thirty Americans were freed.
1953 – The Boston marathon was won by Keizo Yamada with a record time of 2:18:51.
1959 – “Desilu Playhouse” on CBS-TV presented a two-part show titled “The Untouchables.”
1961 – FM stereo broadcasting was approved by the FCC.
1962 – The New Orleans Citizens’ Council offered a free one-way ride for blacks to move to northern states.
1967 – U.S. planes bombed Haiphong for first time during the Vietnam War.
1971 – The U.S. Supreme Court upheld the use of busing to achieve racial desegregation in schools.
1972 – The manned lunar module from Apollo 16 landed on the moon.
1977 – Woody Allen’s film “Annie Hall” premiered.
1981 – A spokesman for the U.S. Nave announced that the U.S. was accepting full responsibility for the sinking of the Nissho Maru on April 9.
1982 – The Activision game Pitfall! was released for the Atari 2600 game system.
1984 – Britain announced that its administration of Hong Kong would cease in 1997.
1985 – In Madrid, Santiago Carillo was purged from the Communist Party. Carillo was a founder of Eurocommunism.
1987 – In Argentina, President Raul Alfonsin quelled a military revolt.
1988 – The U.S. Air Forces’ Stealth (B-2 bomber) was officially unveiled.
1989 – Scientist announced the successful testing of high-definition TV.
1991 – Mikhail Gorbachev became the first Soviet head of state to visit South Korea.
1992 – The worlds largest fair, Expo ’92, opened in Seville, Spain.
1998 – Kenyan runner Moses Tanui, 32, won the Boston Marathon for the second time. He also registered the third fastest time with 2 hours 7 minutes and 34 seconds.
1999 – The Columbine High School massacre was a school shooting that occurred on April 20, 1999, at Columbine High School in Columbine, an unincorporated area of Jefferson County in the American state of Colorado.wiki