Home9NEWS Denver on Twitter "Today marks 21 years. 21 years since 12(04)

9NEWS Denver on Twitter "Today marks 21 years. 21 years since 12(04)

9NEWS Denver on Twitter "Today marks 21 years. 21 years since 12(04)

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Columbine History, Victims, and Impact Rachel's ChallengeColumbine school shooting victims remembered at 25th anniversary vigilColumbine High School Victims Honored 22 Years After Tragedy CBS ColoradoColumbine students, teacher remembered 24 years after tragedy CBS9NEWS Denver on Twitter "Today marks 21 years. 21 years since 12