History of the Day for:
April 22
- 1500: Pedro Alvarez Cabral discovered Brazil.
- 1509: Henry the Eighth ascended the throne of England following the death of his father, Henry the Seventh.
- 1724: German philosopher Immanuel Kant was born.
- 1864: Congress authorized the use of the phrase "In God We Trust" on coins.
- 1876: The first official National League baseball game was held in Philadelphia.
- 1889: The Oklahoma Land Rush began as thousands of homesteaders staked claims.
- 1898: Congress passed the Volunteer Army Act calling for a Volunteer Cavalry, later known as the Rough Riders; President McKinley ordered the blockade of Cuban harbors; The first shot of the Spanish-American War was fired.
- 1904: Nuclear scientist Robert Oppenheimer was born.
- 1930: The United Kingdom, Japan and the United States sign the London Naval Treaty regulating submarine warfare and limiting shipbuilding.
- 1944: World War II: Operation Persecution is initiated – Allied forces land in the Hollandia (currently known as Jayapura) area of New Guinea.
- 1945: World War II: Prisoners at the Jasenovac concentration camp revolt. 520 are killed and 80 escape.
- 1945: World War II: Fuehrerbunker: After learning that Soviet forces have taken Eberswalde without a fight, Adolf Hitler admits defeat in his underground bunker and states that suicide is his only recourse.
- 1954: The Senate Army-McCarthy hearings began.
- 1956: Elvis Presley made his Las Vegas debut at the Frontier Hotel.
- 1964: President Johnson opened the New York World's Fair.
- 1970: The first "Earth Day" was observed.
- 1993: The Holocaust Memorial Museum was dedicated in Washington, D.C.
- 1994: Richard M. Nixon, 37th president of the U.S., died at the age of 81 after suffering a stroke.
- 1996: Humorist Erma Bombeck died at age 69 following a kidney transplant.
- 1997: Haouch Khemisti massacre in Algeria – 93 villagers killed.
- 1997: The Japanese embassy hostage crisis ends in Lima, Peru.
- 1998: Disney's Animal Kingdom opens at Walt Disney World near Orlando, Florida, United States.
- 2000: In a pre-dawn raid, federal agents seize six-year-old Elián González from his relatives' home in Miami, Florida.
- 2000: The Big Number Change takes place in the United Kingdom.
- 2000: Second Battle of Elephant Pass, Tamil Tigers capture a strategic Sri Lankan Army base and hold it for 8 years.
- 2004: Two fuel trains collide in Ryongchon, North Korea, killing up to 150 people.
- 2006: 243 people are injured in pro-democracy protest in Nepal after Nepali security forces open fire on protesters against King Gyanendra.
- 2006: Four Canadian soldiers are killed 75 kilometers north of Kandahar, Afghanistan by a roadside bomb planted by Taliban militants, the worst single day combat loss for the Canadian army since the Korean War.
- 2008: The United States Air Force retires the remaining F-117 Nighthawk aircraft in service.