1. 1493: Pope Alexander VI issued the papal bull “Inter caetera,” dividing the non-Christian world between Spain and Portugal along a north-south line 100 leagues west of the Cape Verde islands.

2. 1886: The Haymarket affair took place in Chicago, culminating in a riot after a peaceful labor demonstration for the eight-hour workday. The riot resulted in several deaths and injuries among both police officers and civilians.

3. 1919: The first transatlantic flight took place, as U.S. Navy flying boat NC-4, commanded by Albert Cushing Read, completed the journey from New York to Lisbon, Portugal.

4. 1926: The United Kingdom’s general strike began, lasting nine days. It was one of the largest strikes in British history, involving around 1.7 million workers from various industries.

5. 1945: The surrender of German forces in the Netherlands, Denmark, and northwest Germany effectively ended the Battle of the Netherlands and World War II in those regions.

6. 1970: The Kent State shootings occurred when Ohio National Guardsmen opened fire on students protesting the Vietnam War at Kent State University, killing four and wounding nine others.

7. 1972: The Don’t Make A Wave Committee, a group of activists protesting nuclear testing, officially changed its name to Greenpeace Foundation. This marked the beginning of what would become one of the world’s most recognizable environmental organizations.

8. 1979: Margaret Thatcher became the first female Prime Minister of the United Kingdom, after her Conservative Party won the general election.

9. 2000: London’s Tate Modern art gallery opened to the public. Housed in the former Bankside Power Station, it has since become one of the most visited modern art galleries in the world.

10. 2007: The Scottish National Party won the Scottish parliamentary election, becoming the largest party and paving the way for Alex Salmond to become the First Minister of Scotland.