Columbine High School principal recites victims’ names every morning New York Post Biden marks 25th anniversary of Columbine shooting The HillNearly 500 People Have Been Killed in School Shootings Since Columbine NewsweekColumbine victim’s sneakers forge a path for his father 25 years later FOX 31 DenverOver 1000 Columbine community members volunteer for day of service 25 years after school shooting CBS News