LITTLETON, Colo. (KDVR) — Thursday marks 24 years since 12 students and one teacher were killed at Columbine High School in Littleton. Over 20 other people were injured during the mass shooting on April 20, 1999.

On this day, we remember the 12 students who were killed:

Cassie Bernall, 17
Steven Curnow, 14
Corey DePooter, 17
Kelly Fleming, 16
Matthew Kechter, 16
Daniel Mauser, 15
Daniel Rohrbough, 15
Rachel Scott, 17
Isaiah Shoels, 18
John Tomlin, 16
Lauren Townsend, 18
Kyle Velasquez, 16

We also remember Columbine teacher and coach Dave Sanders who was also killed. He was 47 years old.

The Columbine Memorial, located at Clement Park, is a safe space for all who wish to honor and remember those who were killed, injured, survived and were affected by that day.

Every year on April 20, classes at Columbine High School are closed so that students and the community can participate in a day of service. This year makes the seventh annual Columbine Day of Service.

“Whether you are a student at Columbine, an alumni of the school, or simply seeking to make a positive impact, we challenge you to make a commitment: a commitment to kindness, a commitment to community, a commitment to gratitude, a commitment to serving others. This year, we are also observing Columbine’s 50th anniversary–and 50 years of community,” the organization said on its website.

In 2022, the Columbine Day of Service generated projects in 10 other countries.