The Columbine High School massacre occurred on Tuesday, April 20, 1999, at Columbine High School in unincorporated Jefferson County, Colorado, near Denver and Littleton. Two teenage students, Eric Harris and Dylan Klebold, carried out a shooting rampage, killing twelve fellow students and a teacher, as well as wounding twenty-four others, before committing suicide. It is considered to be the deadliest school shooting, and the second deadliest attack on a school in United States history after the Bath School disaster.