On March 21

A major explosion at a chemical plant in Yancheng, China, killed 78 people and injured 640 others.

Jack Dorsey sent the first message on the social-media network Twitter.

A man smashed the statue of Phra Phrom at the Erawan Shrine in Bangkok, Thailand, with a hammer, and was subsequently beaten to death by bystanders.

In the West Bank, a number of Palestinian girls complained of breathing difficulties due to strange odors, leading to accusations of poison gas.

The American soap opera Dallas aired the episode "A House Divided", which led to eight months of international speculation on "Who shot J.R.?"

War of Attrition: The Battle of Karameh took place between the Israel Defense Forces and allied troops of the Palestine Liberation Organization and the Jordanian Armed Forces.

The Federal Bureau of Prisons closed Alcatraz Federal Penitentiary on Alcatraz Island (pictured) in San Francisco Bay, California.

Police in Sharpeville, South Africa, opened fire on a group of unarmed black demonstrators who were protesting pass laws, killing 69 people and wounding 180 others.

The Moondog Coronation Ball, generally considered to be the first major rock and roll concert, took place at the Cleveland Arena in Cleveland, Ohio.

The Los Angeles Rams signed Kenny Washington, making him the first African-American player in the National Football League since 1933.

A police squad, acting under orders from Governor of Puerto Rico Blanton Winship, opened fire on demonstrators protesting the arrest of Puerto Rican Nationalist leader Pedro Albizu Campos, killing 21 people and injuring 235 others.

First World War: The German Army opened the Spring Offensive with Operation Michael, attempting to break through the Allied lines and to seize ports on the English Channel.

More than 360 were killed and 20,000 homes were destroyed in the Great Dayton Flood in Dayton, Ohio, U.S.

Queen's Park defeated Clydesdale 2–0 in the final of the inaugural Scottish Cup.

Alexander H. Stephens, Vice President of the Confederate States of America, gave an extemporaneous speech laying out the Confederacy's rationale for seceding from the United States.

The Baháʼí calendar, used in the Baháʼí Faith, began.

During his tour of the United States, the Marquis de Lafayette laid the cornerstone for the Nathanael Greene Monument in Savannah, Georgia.

War of the Sixth Coalition: During their march on Paris, Coalition forces defeated Napoleon's French army on the final day of the Battle of Arcis-sur-Aube.

A large fire destroyed 856 of the 1,100 structures in New Orleans.

Thomas Cranmer, a former archbishop of Canterbury and one of the founders of Anglicanism, was burned at the stake for heresy in Oxford, England.