Two of the country's largest mass shootings have occurred in Colorado: the Columbine High School massacre in 1999 and the Aurora movie theater massacre in 2012. Other notable mass shootings in Colorado include the Colorado YWAM and New Life shootings in 2007, the Colorado Springs Planned Parenthood shooting in 2015, the National Western Complex shootout in Denver in 2016, and the most recent 2021 Boulder shooting in Boulder.