A school shooting and attempted bombing occurred on April 20, 1999, at Columbine High School in Columbine, Colorado, United States. The perpetrators, twelfth-grade students Eric Harris and Dylan Klebold, murdered twelve students and one teacher; ten were killed in the school library, where Harris and Klebold subsequently died by suicide. Twenty-one additional people were injured by gunshots, and gunfire was exchanged with the police. Another three people were injured trying to escape. The Columbine massacre was the deadliest mass shooting at a K-12 school in U.S. history until December 2012. It is still considered one of the most infamous massacres in the U.S. for inspiring many other school shootings and bombings; the word "Columbine" has since become a byword for modern school shootings. As of 2025, Columbine is still both the deadliest mass shooting and school shooting in Colorado, and one of the deadliest mass shootings in the United States.