Gunfire broke out at Marjory Stoneman Douglas High School in Florida Wednesday, killing 17 people in the fourth deadliest school shooting in modern U.S. history.
The suspect, a former student, reportedly pulled the fire alarm at the Parkland school before shooting. Students cowered in their classrooms as bullets rang out.
"It's catastrophic, there really are no words," Broward Sheriff's Department Scott Israel said.
The tragedy is just one of many to occur in American schools throughout the years.
Here is a list of some of the worst school shootings in modern American history
Virginia Polytechnic Institute and State University
In April 2007, a senior student at the university committed the deadliest school shooting in modern U.S. history, killing 32 people and injuring 17 others in two separate attacks on campus — one in a co-ed dormitory and the other in the Engineering, Science and Mechanics building.
Sandy Hook Elementary School
In December 2012, 26 people were killed, including 20 schoolchildren aged 5 and 6, inside the Newton, Conn., school after a 20-year-old entered and opened fire. The gunman killed his mother before heading to the school. After the heinous shooting, he killed himself as police closed in.
University of Texas
On August 1, 1966, a former Marine sharpshooter, 25, opened fire at the University of Texas in Austin. The gunman positioned himself on the observation deck atop the U.T. Tower and shot his targets one-by-one. He killed 14 people and wounded 31 others. He also killed his wife and mother before the attacks. The massacre ended when police located the shooter and fatally shot him.
Columbine High School
Two high school students, ages 17 and 18, opened fire at the Littleton, Colo., school in April 1999. They reportedly spent weeks prepping for the massacre, and killed 13 people while injuring 24. They later committed suicide in the school’s library together.
Red Lake Senior High School
A 16-year-old opened fire at the Red Lake Senior High School in March 2005 after robbing his grandfather of police weapons and a bulletproof vest. He killed his grandfather before heading to the school, where he murdered seven people and wounded five others. He committed suicide after a gun battle with police.
In April 2012, a 43-year-old gunman in California committed Oakland's worst mass killing when he opened fire at the Korean Christian school. Witnesses said the shooter stood up in class and told everyone to get up against the wall while holding a gun. He killed seven people and wounded three others. He fled the school after the murders and later surrendered at a supermarket. The gunman pleaded no contest and is serving life without the possibility of parole.