On April 22:
1451 Isabella I of Castile was born.
1500 Portuguese navigator Pedro Álvares Cabral became the first European to sight Brazil.
1529 Treaty of Saragossa divided the eastern hemisphere between Spain and Portugal along a line 297.5 leagues or 17° east of the Moluccas.
1692 James Stirling, Scottish mathematician, was born (d. 1770) .
1707 Henry Fielding, English author, was born (d. 1754) .
1724 Immanuel Kant, German philosopher, was born (d. 1804) .
1809 Battle of Eckmühl: Austrian army defeated by the First French Empire army led by Napoleon I of France and driven over the Danube at Regensburg.
1832 Julius Sterling Morton, Arbor Day founder, was born (d. 1902) .
1836 Texas Revolution: A day after the Battle of San Jacinto, forces under Texas General Sam Houston captured Mexican General Antonio López de Santa Anna.
1870 Vladimir Lenin, Russian revolutionary, was born (d. 1924) .
1889 At high noon, thousands rushed to claim land in the Land Run of 1889. Within hours the cities of Oklahoma City and Guthrie were formed with populations of at least 10,000.
1898 Spanish-American War: The United States Navy began a blockade of Cuban ports and the USS Nashville captured a Spanish merchant ship.
1912 Pravda, the “voice” of the Communist Party of the Soviet Union, began publication in Saint Petersburg.
1914 Jan de Hartog, Dutch writer, was born (d. 2002) .
1915 The use of poison gas in World War I escalated when chlorine gas was released as a chemical weapon in the Second Battle of Ypres.
1916 Yehudi Menuhin, American-born violinist, was born (d. 1999) .
1923 Aaron Spelling, American television producer, was born (d. 2006) .
1925 George Cole, English actor, was born.
1930 The United Kingdom, Japan and the United States signed the London Naval Treaty regulating submarine warfare and limiting shipbuilding.
1936 The alliance between the Ratana Church and the Labour Party was cemented at a meeting between Tahupotiki Wiremu Ratana and Prime Minister Michael Joseph Savage
1937 Jack Nicholson, American actor, was born.
1944 World War II: Operation Persecution was initiated – Allied forces landed in the Hollandia area of New Guinea.
1944 Steve Fossett, American adventurer, was born (d. 2007) .
1945 World War II: Prisoners at the Jasenovac concentration camp revolted. 520 were killed and 80 escaped.
1945 World War II: Fuehrerbunker: After learning that Soviet forces have taken Eberswalde without a fight, Adolf Hitler admited defeat in his underground bunker and stated that suicide was his only recourse.
1950 Peter Frampton, English musician, was born.
1954 Red Scare: The Army-McCarthy Hearings began.
1964 The 1964-1965 New York World’s Fair opened for its first season.
1969 British yachtsman Sir Robin Knox-Johnston completed the first solo non-stop circumnavigation of the world.
1970 The first Earth Day was celebrated.
1979 The Albert Einstein Memorial was unveiled at The National Academy of Sciences in Washington, DC.
1992 Explosion in Guadalajara, Mexico – 206 people were killed, nearly 500 injured and 15,000 left homeless.
1993 The Holocaust Memorial Museum in Washington, D.C. was dedicated.
1993 – Version 1.0 of the Mosaic web browser was released.
1997 Haouch Khemisti massacre in Algeria – 93 villagers killed.
1997 – The Japanese embassy hostage crisis ended in Lima, Peru.
1998 Disney’s Animal Kingdom opened at Walt Disney World.
2000 – The Big Number Change took place in the United Kingdom.
2000 Second Battle of Elephant Pass, Tamil Tigers captures a strategic Sri Lankan Army base and held it for 8 years.
2004 Two fuel trains collided in Ryongchon, North Korea, killing up to 150 people.
2006 243 people were injured in pro-democracy protest in Nepal after Nepali security forces open fire on protesters against King Gyanendra.
2008 – Homepaddock blog was launched.
2008 The United States Air Force retired the remaining F-117 Nighthawk aircraft in service.
2010 – Deepwater Horizon, an oil rig owned by BP and Transocean, sankto the bottom of the Gulf Of Mexico after a blowout two days earlier.
Sourced from NZ History Online & Wikipedia