Newtown, Conn. – On December 14, 2012, 20-year-old Adam Lanza fatally shot 20 children at Sandy Hook Elementary School. They were between the ages of six and seven years old. He also killed six adult staff members.
Washington D.C. — A former Navy reservist shot and killed 12 people on September 16, 2013, at a military facility. The gunman was killed.
Tyrone, Mo. – On Feb. 27, 2015, Joseph Jesse Aldridge killed seven people — four of them relatives — in a door-to-door shooting spree before killing himself.
Waco, Tex. – Nine people were killed and many more were injured after two biker gangs began firing at each other at a motorcycle club on May 17, 2015.
Charleston, S.C. – Dylann Roof shot and killed nine people during a racially motivated shooting in a predominantly African-American church on June 17, 2015.
Chattanooga, Tenn. – A gunman named Mohammod Youssuf Abdulazeez entered two military facilities on July 16, 2015, and killed four Marines and injured others, before he was killed.
Umpqua, Ore. – On October 1, 2015, Chris Harper Mercer killed nine people and injured seven to nine more at Umpqua Community College before two police officers shot him. Mercer then committed suicide.
San Bernardino, Calif. – 14 people were killed and another 21 injured after Syed Farook and Tashfeen Malik opened fire during a holiday party on December 2, 2015. The pair were later killed during a shootout with police.
Orlando, Fla. – 50 people were killed and 53 wounded on June 11, 2016, at Pulse, a gay nightclub. Just before the shooting, suspected killer Omar Mateen called 911 and pledged his allegiance to the terror group ISIS. Mateen was also shot an killed by police on the scene.