This Day in History: April 4

1581: Francis Drake knighted by Queen Elizabeth I aboard 'Golden Hind' at Deptford, England

Queen Elizabeth I of England knights Francis Drake aboard his ship, the Golden Hind, for his successful circumnavigation of the globe and his contributions to the defeat of the Spanish Armada.

1655: Battle at Postage Farina, Tunis: English fleet beats Barbary pirates

The English navy, led by Admiral Robert Blake, defeats the Barbary pirates in the Battle of Postage Farina off the coast of Tunisia. The victory helps secure English trade routes in the Mediterranean.

1789: 1st US Congress begins regular sessions during George Washington's presidency at Federal Hall, NYC (ending 1791)

The United States Congress holds its first regular session in Federal Hall in New York City. The session was presided over by George Washington, who was the first President of the United States.

1949: North Atlantic Treaty Organization (NATO) treaty signed in Washington, D.C.

Twelve nations, including the United States, Canada, and several European countries, sign the North Atlantic Treaty, establishing NATO as a military alliance to defend against potential Soviet aggression during the Cold War.

1968: US civil rights activist Martin Luther King Jr. is assassinated by James Earl Ray at the Lorraine Hotel in Memphis, Tennessee

Martin Luther King Jr., a prominent leader in the American civil rights movement, is assassinated by James Earl Ray. King's death sparks protests and riots across the United States.

1973: World Trade Center, then the world's tallest building, opens in New York (110 stories). Later destroyed in 9/11 terrorist attacks.

The World Trade Center complex, consisting of two towers, is officially opened in New York City. The towers become an iconic symbol of the city's skyline until they are tragically destroyed in the terrorist attacks of September 11, 2001.

1975: Microsoft is founded as a partnership between Bill Gates and Paul Allen to develop and sell BASIC interpreters for the Altair 8800

Bill Gates and Paul Allen establish Microsoft, a software company that goes on to become one of the largest and most influential technology companies in the world.

1969: Denton Cooley implants the first artificial heart

Denton Cooley successfully implants an artificial heart in patient Haskell Karp, keeping him alive for 65 hours until a human heart transplant can