http://en.wikipedia.org/wiki/Columbine_High_School_massacreThe Columbine High School massacre occurred on Tuesday, April 20, 1999, at Columbine High School in unincorporated Jefferson County, Colorado (the CDP of Columbine) near Denver and Littleton. Two students, Eric Harris and Dylan Klebold, embarked on a shooting rampage, killing 12 students and a teacher, as well as wounding 23 others, before committing suicide. It is the fourth-deadliest school killing in United States history, after the 1927 Bath School disaster, 2007 Virginia Tech massacre and the 1966 University of Texas massacre.