Columbine High School massacre

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 12 students and one teacher. Ten students were killed in the school library, where the pair subsequently committed suicide. Twenty-one additional people were injured by gunshots, and gunfire was also exchanged with the police. Another three people were injured trying to escape the school. At the time, it was the deadliest school shooting in U.S. history. The crime has inspired several copycats and "Columbine" has become a byword for school shootings.

In addition to the shootings, the attack involved several homemade bombs. Two of these were placed in the cafeteria, powerful enough to kill or seriously injure all people within the area, although they failed to detonate. Their cars in the parking lots were made into bombs which also failed to detonate, and at another location away from the school, two bombs were set up as diversions, only one of which partially detonated. The motive remains unclear; but Harris and Klebold planned the massacre for around a year, and hoped the massacre would cause the most deaths in U.S. history, which then meant exceeding the death toll of the Oklahoma City bombing; USA Today referred to the Columbine massacre as "planned as a grand, if badly implemented, terrorist bombing."

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