4 April 1561

Georgian Airways Flight 834 crashed at N'djili Airport in Kinshasa, killing 32 people and leaving one survivor.

The current flag of Hong Kong (pictured) was adopted for post-colonial use during the Third Session of the Seventh National People's Congress.

Evan Mecham, Governor of Arizona, was removed from office after being convicted in his impeachment trial.

Bill Gates and Paul Allen founded Microsoft in Albuquerque, New Mexico, to develop and sell BASIC interpreters for the Altair 8800.

Vietnam War: On a mission to evacuate children from South Vietnam, a U.S. Air Force plane crash-landed at Tan Son Nhut Air Base, killing 78 children and 60 others.

A year after the completion of the second of the complex's twin towers, the World Trade Center in New York City was officially dedicated.

A C-141, dubbed the Hanoi Taxi, flew the last mission of Operation Homecoming to return American prisoners of war from Vietnam.

American civil rights leader Martin Luther King Jr. (pictured) was assassinated in Memphis, Tennessee.

Twelve nations signed the North Atlantic Treaty, establishing NATO, an international military alliance whereby its member states agree to mutual defense in response to an attack by any external party.

An earthquake hit the Kangra Valley in India, killing at least 20,000 people and destroying 100,000 buildings.

William Henry Harrison became the first U.S. president to die in office, sparking a brief constitutional crisis regarding questions of presidential succession that were unanswered by the U.S. Constitution.

Napoleon abdicated as Emperor of the French and named his son Napoleon II to replace him.

Queen Elizabeth I knighted Francis Drake for completing a circumnavigation of the world.

The Byzantine Empire and the Republic of Venice signed a five-year peace treaty.

Roman consul Agrippa Menenius Lanatus celebrated a triumph for a military victory over the Sabines.

The impeachment of President Yoon Suk Yeol of South Korea in response to his declaration of martial law is unanimously upheld by the country's Constitutional Court, ending his presidency.

Russo-Ukrainian war: The Battle of Chasiv Yar begins.

Finland becomes a member of NATO after Turkey accepts its membership request.

Georgian Airways Flight 834 crashes at N'djili Airport in Kinshasa, killing 32.

A magnitude 7.2 earthquake hits south of the Mexico-USA border, killing at least two and damaging buildings across the two countries.

France announces its return to full participation of its military forces within NATO.

The MPLA government of Angola and UNITA rebels sign a peace treaty ending the Angolan Civil War.

Space Shuttle program: Space Shuttle Columbia is launched on STS-83. However, the mission is later cut short due to a fuel cell problem.

Comet Hyakutake is imaged by the USA Asteroid Orbiter Near Earth Asteroid Rendezvous.