On this day in 1999, two teenage gunmen kill 13 people in a shooting spree at Columbine High School in Littleton, Colorado, south of Denver.
This Day In History: April 20
This Day In History: April 20
On this day in 1999, two teenage gunmen kill 13 people in a shooting spree at Columbine High School in Littleton, Colorado, south of Denver.