Even before 14 students and three staff members were killed at Stoneman Douglas High School in Parkland, Florida, schools and universities ranked as the most deadly type of venue for the worst mass shootings in modern US history.
Since 1999, so many schools have been targeted by gunmen that the deaths of 12 students and a teacher at Columbine High School no longer make the list of the 10 worst American gun massacres in recent decades.
That list counts incidents in which 14 or more people were killed, not including the attackers. Here is a look at the fatalities in those cases, by type of place.