Eric Walker removed 1999-04 Columbine High School massacre from Colorado
Eric Walker placed 1999-04 Columbine High School massacre under Columbine, Colorado
Eric Walker removed 1999-04 Columbine High School massacre from Shootings and terrorist attacks
Eric Walker placed 1999-04 Columbine High School massacre under Shootings and terrorist attacks in the United States
Eric Walker added Columbine anniversary: guns are still the problem behind mass shootings - Vox to a number of topics
Eric Walker added What’s New About Conspiracy Theories? | The New Yorker to a number of topics
Eric Walker added a number of topics and a number of links to Massacres, and added Massacres to Murder and violent crime
Eric Walker added a number of links to 1999-04 Columbine High School massacre, and added 1999-04 Columbine High School massacre to Colorado, Shootings and terrorist attacks and Massacres
Eric Walker added a number of topics and a number of links to Colorado, and added Colorado to US states and territories
Eric Walker added a number of topics and a number of links to Shootings and terrorist attacks, and added Shootings and terrorist attacks to Extremism and state-sponsored violence and Murder and violent crime