| | 1500 - Portuguese navigator Pedro Álvares Cabral becomes the first European to sight Brazil. |
| | 1509 - Henry VIII ascends the throne of England after the death of his father. |
| | 1529 - Treaty of Saragossa divides the eastern hemisphere between Spain and Portugal along a line 297.5 leagues or 17° east of the Moluccas. |
| | 1836 - Texas Revolution: A day after the Battle of San Jacinto forces under Texas General Sam Houston capture Mexican General Antonio López de Santa Anna. |
| | 1863 - American Civil War: Grierson's Raid begins – troops under Union Colonel Benjamin Grierson attack central Mississippi. |
| | 1864 - The U.S. Congress passes the Coinage Act which mandates that the inscription "In God We Trust" be placed on all coins minted as United States currency. |
| | 1876 - The National League of Baseball plays its first game, establishing the template for the modern game. |
| | 1889 - At high noon, thousands rush to claim land in the Land Run of 1889. Within hours the cities of Oklahoma City and Guthrie are formed with populations of at least 10,000. |
| | 1898 - Spanish-American War: The United States Navy begins a blockade of Cuban ports and the USS Nashville captures a Spanish merchant ship. |
| | 1912 - Pravda, the "voice" of the Communist Party of the Soviet Union, begins publications in Saint Petersburg. |
| | 1915 - The use of poison gas in World War I escalates when chlorine gas is released as a chemical weapon in the Second Battle of Ypres. |
| | 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 initiated – Allied forces land in the Hollandia (currently known as Jayapura) area of New Guinea. |
| | 1945 - World War II: 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. |
| | 1946 - The first installment of the popular Japanese comic strip, Sazae-san, is published in the Fukunichi Shimbun. |
| | 1954 - Red Scare: Army-McCarthy Hearings begin. |
| | 1964 - The 1964-1965 New York World's Fair opens for its first season. |
| | 1970 - First Earth Day celebrated. |
| | 1971 - John Kerry, dressed in combat fatigues, testifies on his views of the Vietnam War before the United States Senate Foreign Relations Committee |
| | 1972 - Vietnam War: Increased American bombing in Vietnam prompts antiwar protests in New York City, San Francisco, and Los Angeles. |
| | 1975 - Barbara Walters signs a five-year $5 million contract with the American Broadcasting Corporation (ABC), becoming the highest paid television newsperson. |
| | 1978 - One Love Peace Concert held at National Heroes Stadium in Kingston, Jamaica. Bob Marley united the two opposing political leaders at this concert bringing peace to the civil war ridden streets of Kingston, Jamaica. |
| | 1983 - The German magazine, Der Stern claims that Adolf Hitler's diaries were found in a wreckage in East Germany. |
| | 1990 - The Anti-Drug video Cartoon All-Stars to the Rescue is released. |
| | 1992 - 1992 explosion in Guadalajara, Mexico ; 206 people were killed, nearly 500 injured and 15,000 were left homeless |
| | 1993 - The Holocaust Memorial Museum in Washington, DC is dedicated. |
| | 1993 - The web browser Mosaic version 1.0 is released. |
| | 1997 - Haouch Khemisti massacre in Algeria; 93 villagers killed. |
| | 1997 - A 126-day hostage crisis at the residence of the Japanese ambassador in Lima, Peru ends after government commandos storm and capture the building, rescuing 71 hostages. One hostage dies of a heart attack, two soldiers are killed from rebel fire, and all 14 rebels are slain. |
| | 2000 - In a predawn 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. |
| | 2004 - Two fuel trains collide in Ryongchon, North Korea, killing up to 150 people. |
| | 2006 - 243 people were injured in pro-democracy protest in Nepal after Nepali security forces opened 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. |