On this day, April 20 ...

1999: The Columbine High School massacre takes place in Colorado as two students shoot and kill 12 classmates and one teacher before taking their own lives.

Also on this day:

  • 1898: The United States moves closer to war with Spain as President William McKinley signs a congressional resolution passed the day before recognizing Cuban independence and authorizing U.S. military intervention to achieve that goal.
  • 1914: The Ludlow Massacre takes place when the Colorado National Guard opens fire on a tent colony of striking miners.
  • 1938: “Olympia,” Leni Riefenstahl’s documentary about the 1936 Berlin Olympic games, is first shown in Nazi Germany.
  • 1971: The U.S. Supreme Court unanimously upholds the use of busing to achieve racial desegregation in schools.
  • 1971: National Public Radio makes its on-air debut with live coverage of a U.S. Senate hearing on the Vietnam War.
  • 1972: Apollo 16’s lunar module, carrying astronauts John W. Young and Charles M. Duke Jr., lands on the moon.
  • 1977: The U.S. Supreme Court, in Wooley v. Maynard, rules 6-3 that car owners could refuse to display state mottoes on license plates, such as New Hampshire’s “Live Free or Die.”
  • 1986: Following an absence of six decades, Russian-born pianist Vladimir Horowitz performs in the Soviet Union to a packed audience at the Grand Hall of the Tchaikovsky Conservatory in Moscow.
  • 1992: The Freddie Mercury Tribute Concert for AIDS Awareness takes place at London’s Wembley Stadium.
  • 1992: Comedian Benny Hill dies in his Greater London flat at age 68.
  • 2003: U.S. Army forces take control of Baghdad from the Marines in a changing of the guard that thins the military presence in the capital.
  • 2010: An explosion on the Deepwater Horizon oil platform, leased by BP, kills 11 workers and causes a blow-out that begins spewing an estimated 200 million gallons of crude into the Gulf of Mexico. (The well would be finally capped nearly three months later.)
  • 2014: Rubin “Hurricane” Carter, the boxer whose wrongful murder conviction in New Jersey became an international symbol of racial injustice, dies in Toronto at age 76.
  • 2018: U.S. health officials tell consumers to throw away any store-bought romaine lettuce and warn restaurants not to serve it amid an E. coli outbreak that sickened more than 50 people in several states.
  • 2018: Wells Fargo agrees to pay $1 billion to federal regulators to settle charges stemming from misconduct at its mortgage and auto lending businesses; it is the latest punishment levied against the banking giant for widespread customer abuses.
  • 2018: The Democratic Party files a lawsuit accusing the Donald Trump presidential campaign, Russia, WikiLeaks and Trump’s son and son-in-law of conspiring to undercut Democrats in the 2016 election by stealing tens of thousands of emails and documents.