When:
April 20, 2017 all-day
2017-04-20T00:00:00-06:00
2017-04-21T00:00:00-06:00
Where:
http://www.history.com/topics/columbine-high-school-shootings

Memorial at Columbine High School
On 20 April 1999, at Columbine High School at Littleton, Colorado, two students killed 12 other students, a teacher and then themselves.
Image: CC BY 3.0