Chernobyl nuclear accident
A devastating environmental catastrophe occurred early this morning in 1986 when an explosion and fire at the Chernobyl nuclear power plant in Ukraine released large amounts of radioactive material into the atmosphere.

1992 Betty Boothroyd became the first woman to be elected speaker of the House of Commons; she held the post until 2000.

Benito Mussolini executed
Italian dictator Benito Mussolini, “Il Duce,” who, after a series of military misadventures, became unpopular even among his fellow Fascists, was captured while trying to flee Italy and was executed on this day in 1945.

1429 French national heroine Joan of Arc and her troops entered the besieged city of Orléans during the Hundred Years' War.

George Washington inaugurated
George Washington, the first president of the United States, was inaugurated this day in 1789 in Federal Hall in New York City, addressing his constituency on “the proceedings of a new and free government.”

May Day founded
On this day in 1889, May Day—traditionally a celebration of the return of spring, marked by dancing around a Maypole—was first observed as a labour holiday, designated as such by the International Socialist Congress.

1611 The King James Version of the Bible was first published.

Margaret Thatcher elected prime minister of Britain
On this day in 1979, Margaret Thatcher of the Conservative Party was elected British prime minister, becoming the first woman in Europe to hold that post and later the longest continuously serving British premier since 1827.

2000: Ken Livingstone voted London mayor
The London Mayoral contest ends in victory for Ken Livingstone, the independent candidate and maverick MP expelled from the Labour Party.

1961 Alan Shepard, Jr., made a 15-minute suborbital flight in the Freedom 7 spacecraft, becoming the first U.S. astronaut to travel in space.

Hindenburg disaster
On this day in 1937, while landing at Lakehurst, New Jersey, on its first transatlantic crossing of the year, the German dirigible Hindenburg burst into flames and was destroyed, killing 36 of the 97 persons aboard.

Theatre Royal opened
The Theatre Royal, built by the dramatist Thomas Killigrew for his company of actors and now commonly known as the Drury Lane Theatre, opened in London this day in 1663 and is the oldest English theatre still in use.

World War II in Europe ended
Following Germany's unconditional surrender, World War II in Europe officially ended at midnight on this day in 1945, although the war in the Pacific continued until the Japanese surrender in September.

Fourth and final voyage of Christopher Columbus launched
On this day in 1502, master navigator and admiral Christopher Columbus, long considered the “discoverer” of the New World, set sail from Cádiz, Spain, on his fourth and final voyage, hoping to find a passage to Asia.

Nelson Mandela inaugurated as president of South Africa
Nelson Mandela, whose efforts to end apartheid led to his imprisonment (1962–90) and earned him a share (with F.W. de Klerk) of the 1993 Nobel Peace Prize, became president of South Africa this day in 1994.