Historical timeline for March 21

China Eastern Airlines Flight 5735 crashes in Guangxi, China, killing 132 people.

The 2019 Xiangshui chemical plant explosion occurs, killing at least 47 people and injuring 640 others.

The social media site Twitter (now officially named X) is founded.

Pope John Paul II makes his first ever pontifical visit to Israel.

Bertrand Piccard and Brian Jones become the first to circumnavigate the Earth in a hot air balloon.

The United Nations Framework Convention on Climate Change enters into force.

Namibia becomes independent after 75 years of South African rule.

Transbrasil Flight 801 crashes into a slum near São Paulo/Guarulhos International Airport, killing 25 people.

Debi Thomas becomes the first African American to win the World Figure Skating Championships.

Canadian paraplegic athlete and humanitarian Rick Hansen begins his circumnavigation of the globe in a wheelchair in the name of spinal cord injury medical research.

The first cases of the 1983 West Bank fainting epidemic begin; Israelis and Palestinians accuse each other of poison gas, but the cause is later determined mostly to be psychosomatic.

Cold War: American President Jimmy Carter announces a United States boycott of the 1980 Summer Olympics in Moscow to protest the Soviet–Afghan War.

San Diego Comic-Con, the largest pop and culture festival in the world, hosts its inaugural event.

The first Earth Day proclamation is issued by Joseph Alioto, Mayor of San Francisco.

Battle of Karameh in Jordan between the Israel Defense Forces and the combined forces of the Jordanian Armed Forces and PLO.

Martin Luther King Jr. leads 3,200 people on the start of the third and finally successful civil rights march from Selma to Montgomery, Alabama.

Ranger program: NASA launches Ranger 9, the last in a series of uncrewed lunar space probes.

Alcatraz Federal Penitentiary closes.

Apartheid: Sharpeville massacre, South Africa: Police open fire on a group of black South African demonstrators, killing 69 and wounding 180.

Alan Freed presents the Moondog Coronation Ball, the first rock and roll concert, in Cleveland, Ohio.