On March 21, 1980...

  • U.S. president Jimmy Carter announces that the United States will boycott the 1980 Summer Olympic Games scheduled to take place in Moscow that summer, in protest of the Soviet Union's refusal to remove its troops from Afghanistan.
  • The crime boss of the South Philadelphia mafia, Angelo Bruno, is shot in the back of the head with a shotgun and killed by an unknown assailant while sitting in his car in front of his home. The killing sets off a brutal mob war that would claim 28 lives between 1980 and 1985. It is believed that Bruno's own consigliere, Antonio Caponigro, was behind the hit, as Bruno had just resumed speaking to federal investigators the day before. Caponigro's own dead body will be found in the trunk of a car in New York just a few weeks later.
  • The iconic season finale of the third season of the popular TV show Dallas is broadcast for the first time. In this famous cliffhanger episode entitled "A House Divided," main character J.R. Ewing is mysteriously shot, leading to the catchphrase "Who Shot J.R.?" as America spends all spring and summer pondering who the mysterious shooter might be.
  • Howard Witkin, a glass company executive, is shot to death at his Santa Clara townhouse in a murder-for-hire scheme. His ex-wife Judith Barnett's second husband Robert Singer is convicted of first degree murder for hiring hit men to do the job, apparently so that he could get his hands on Witkin's money when it was inherited by Judith and Howard's children. However in a twist, ten years later it is discovered that Judith herself actually masterminded the hit, with Singer covering for her, and she is convicted of first degree murder in 1994.
  • Walenty Badylak, a Polish baker and veteran of Poland's wartime Underground Home Army, sets himself ablaze in Krakow's Main Square and dies from self-immolation in protest against the Polish communist regime's refusal to acknowledge the Katyn Massacre.
  • Cartoonist Nicole Hollander's long-running daily newspaper comic strip Sylvia is published for the first time. The strip will run all the way until 2012.
  • The legendary boxing rivalry between American Bobby Chacon and Mexican Rafael Limón continues with Chacon-Limón III, held at the Forum in Los Angeles. Chacon prevails in a closely fought, 10-round split decision.
  • English post-punk band The Pop Group releases its genre-defining (and -defying) second studio album For How Much Longer Do We Tolerate Mass Murder?
  • Brazilian soccer legend Ronaldinho is born in Porto Alegre, Brazil.