Survivors of the Columbine High School shooting have been speaking at a remembrance ceremony in Denver to mark the twentieth anniversary of the massacre.
Twelve students and a teacher were murdered by two teenagers.
One former student, Patrick Ireland, who was injured by bullets, said no one from the school or surrounding community had emerged unscathed.
The event was the culmination of three days of commemorations. Earlier, members of the public left flowers and cards at a memorial to the victims.
Columbine students and staff also marked the day by taking part in community service projects.