2003 The World Health Organization (WHO) issued a worldwide health alert, one of the first in a decade, regarding an illness it later called severe acute respiratory syndrome (SARS) that struck hundreds of people in China, Hong Kong, and Vietnam.

The planet Uranus discovered
English astronomer William Herschel observed this day in 1781 the seventh planet from the Sun, Uranus—first described by him as “a curious either nebulous star or perhaps a comet” and named for the father of the god Saturn.

2018 English theoretical physicist Stephen Hawking, who was best known for his work on the physics of black holes and for the book A Brief History of Time: From the Big Bang to Black Holes (1988), died at age 76.

Julius Caesar assassinated on the Ides of March
In 44 Roman dictator Julius Caesar was launching a series of political and social reforms when he was assassinated this day, the Ides of March, by a group of nobles, among whom were Cassius and Brutus.

My Lai Massacre
On this day in 1968, during the Vietnam War, U.S. soldiers dispatched on a search-and-destroy mission killed as many as 500 unarmed villagers in the hamlet of My Lai, considered a stronghold of the Viet Cong.

Vote to end apartheid
On this day in 1992, nearly 69 percent of white South African voters backed F.W. de Klerk's reforms—which included the repeal of racially discriminatory laws—and effectively endorsed the dismantling of apartheid.

1965 Soviet cosmonaut Aleksey Arkhipovich Leonov, after passing through an air lock on the spacecraft Voskhod 2, became the first man to walk in space.

Iraq War begins
On this day in 2003, U.S. President George W. Bush ordered air strikes on Baghdad, thus launching the Iraq War to oust dictator Saddam Hussein, who was believed (wrongly) to be manufacturing weapons of mass destruction.

AUM subway attack
Top leaders of AUM Shinrikyo (Japanese: “AUM Supreme Truth”), a Japanese Buddhist sect founded in 1987 by Asahara Shoko, released nerve gas into a Tokyo subway this day in 1995, killing 12 people and injuring thousands.

Closing of Alcatraz prison
The U.S. federal prison on San Francisco Bay's Alcatraz Island, which had held some of the most dangerous civilian prisoners—including Al Capone and Robert Stroud, the “Birdman of Alcatraz”—was closed this day in 1963.

Murder at Jamestown
Opechancanough, brother of Chief Powhatan and his successor as the leader of the Powhatan Indian empire, led an attack on the Jamestown Colony this day in 1622, killing at least 347 colonists and initiating the Powhatan War.

2001 Although designed for only 5 years of service, the Soviet/Russian space station Mir ended 15 years in orbit when it reentered Earth's atmosphere, falling into the South Pacific Ocean.

Exxon Valdez Alaskan oil spill
On this day in 1989, the oil tanker Exxon Valdez ran aground, spilling some 11 million gallons (41 million litres) of oil into Prince William Sound in Alaska and creating the largest oil spill in U.S. history up to that time.

Robert the Bruce crowned king of Scotland
Robert the Bruce, crowned Scottish king at Scone this day in 1306, freed Scotland from English rule, winning the decisive Battle of Bannockburn (1314) and confirming Scottish independence in the Treaty of Northampton (1328).

2005 Sixteen years after being cancelled, the BBC sci-fi series Doctor Who returned to television with a new episode, with Christopher Eccleston appearing in the title role.