Here's How People Paid Tribute To The Victims Of Columbine 20 Years After The School Shooting
Twelve students and a teacher were killed in what was, at the time, the worst school shooting in the nation's history.
Twenty years ago today, 13 people were killed in a mass shooting at Columbine High School in Colorado, a tragedy that marked the beginning of an era in which the US has repeatedly had to grapple with gun violence in schools.
On April 20, 1999, two high school seniors carried out a planned attack on their school in Littleton, fatally shooting 12 classmates and a teacher before turning their weapons on themselves.
It was, at the time, the deadliest school shooting in the nation's history. The massacre led to a wave of modern school security measures and a heightened awareness of threats of violence.
Here's how people paid tribute to the victims on the 20th anniversary of the 1999 massacre.