A high school
outside of Denver
. Just a perfectly normal, stereotypical high school, until a couple of sickos shot up the place. The death toll stood at thirteen, but if you count Dylan & Eric, the shooters, it came to fifteen.
See also: Columbine
, school shooting
It's a good thing Dylan and Eric's duffel bag bombs didn't detonate, or the Columbine High School library would've fallen into the cafeteria, killing hundreds.