The man charged with killing seven people at an Independence Day parade confessed to police that he unleashed a hail of bullets from a rooftop in suburban Chicago and then fled to the Madison, Wisconsin, area, where he contemplated shooting up an event there.

For many people, the mass shooting that killed at least seven people and injured 30 others in a Chicago suburb on July 4 was yet another reminder that any place, any event in the U.S. can turn dangerous or deadly.