FILE - British Prime Minister Margaret Thatcher (AP Photo/Gerald Penny, File)

On this day, May 3 …

1979: Conservative Party leader Margaret Thatcher is chosen to become Britain’s first female prime minister as the Tories oust the incumbent Labour government in parliamentary elections.

Also on this day:

1469: Niccolo Machiavelli is born in Florence, Italy.
1802: Washington, D.C., is incorporated as a city.
1913: Clorox has its beginnings as five entrepreneurs agree to set up a liquid bleach factory in Oakland, Calif.
1916: Irish nationalists Padraic Pearse, Thomas Clarke and Thomas MacDonagh are executed by a British firing squad for their roles in the Easter Rising, an armed insurrection in Ireland during Easter Week.
1948: The Supreme Court, in Shelley v. Kraemer, rules that covenants prohibiting the sale of real estate to African-Americans or members of other racial groups are legally unenforceable.
1952: The Kentucky Derby is televised nationally for the first time on CBS.
1960: The Harvey Schmidt-Tom Jones musical "The Fantasticks" begins a nearly 42-year run at New York’s Sullivan Street Playhouse.

1978: Spam email is born as Gary Thuerk, a marketing executive for the Digital Equipment Corp. of Maynard, Mass., transmits an unsolicited sales pitch for a new line of computers to 400 prospective customers on ARPANET, a precursor to the Internet; the stunt generates some business, as well as complaints.
1978: "Sun Day" takes place on a Wednesday as thousands of people extolling the virtues of solar energy hold events across the country.
1986: In NASA’s first post-Challenger launch, an unmanned Delta rocket loses power in its main engine shortly after liftoff, forcing safety officers to destroy it by remote control.

In this May 2, 2012 file photo, Kate and Gerry McCann pose for the media with a missing poster depicting an age progression computer-generated image of their daughter Madeleine at nine years of age, to mark her birthday and the 5th anniversary of her disappearance during a family vacation in southern Portugal in May 2007. (AP Photo/Sang Tan, File)

2007: British girl Madeleine McCann vanishes during a family vacation in Portugal nine days before her fourth birthday; her disappearance remains unsolved.
2009: Mexican President Felipe Calderon tells state television a nationwide shutdown and an aggressive informational campaign appears to have helped curtail an outbreak of swine flu in Mexico.
2014: California Chrome pulls away down the stretch for a dominant win at the 140th Kentucky Derby.
2018: A federal grand jury in Detroit indicts former Volkswagen CEO Martin Winterkorn on charges stemming from the company’s diesel emissions cheating scandal.