On May 1

The evacuation of nearly 88,000 people began when a wildfire swept through Fort McMurray, Alberta, Canada, and burned for another 14 months, becoming the costliest disaster in Canadian history.

In Major League Baseball, Rickey Henderson broke the record for stolen bases on the same night that Nolan Ryan broke his own record for no-hitters.

Argentine president Juan Perón expelled Montoneros from a demonstration in the Plaza de Mayo in Buenos Aires, forcing the group to become a clandestine organization.

Gwendolyn Brooks became the first African American to receive the Pulitzer Prize for Poetry.

Sicilian separatist Salvatore Giuliano and his gang fired into a crowd of May Day marchers near Piana degli Albanesi, Sicily, killing 11 and wounding 33.

Second World War: British and Indian forces conducted a successful airborne assault on a Japanese artillery battery during the advance to liberate Rangoon, Burma.

Citizen Kane, a widely acclaimed film by actor and director Orson Welles, premiered.

New York City's Empire State Building (pictured), at the time the tallest building in the world, opened.

A dust explosion at a coal mine near Scofield, Utah, U.S., killed at least 200 miners.

The original Chicago Board of Trade Building opened for business.

Moses Fleetwood Walker (pictured), the last African American in Major League Baseball until Jackie Robinson, played his first game for the Toledo Blue Stockings.

War of the Pyrenees: France regained nearly all the land it lost to Spain the previous year with its victory in the Second Battle of Boulou.

The Marriage of Figaro (audio featured), an opera buffa by Wolfgang Amadeus Mozart, premiered at the Burgtheater in Vienna.

The secret society known as the Order of Illuminati was founded by Adam Weishaupt and Adolph Freiherr Knigge in Ingolstadt, Bavaria, Germany.

Under the terms of the Acts of Union, the Kingdoms of England and Scotland merged to form the Kingdom of Great Britain, with a single parliament and government based in Westminster.

Francis Nicholson and James Blair organize five May Day orations given by students of the College of William & Mary, leading to the establishment of Williamsburg as Virginia's new capital.

Dutch–Portuguese War: Portuguese and Spanish forces recaptured the Brazilian city of Bahia, which had previously been captured by the Dutch Republic.

Stephen Báthory and Anna Jagiellon were crowned as the elected rulers of the Polish–Lithuanian Commonwealth.

Norman mercenaries landed at Bannow Bay in Leinster, beginning the Norman invasion of Ireland.

The Nea Ekklesia church in Constantinople, on which many later cross-in-square Eastern Orthodox churches were based, was consecrated.