Orlando nightclub rampage adds to sad history of U.S. mass shootings

A gunman opened fire in a crowded gay dance club in Orlando, Fla., early Sunday morning, leaving at least 50 people dead and 53 injured in the worst modern mass shooting in U.S. history.

Authorities identified the attacker as Omar Mateen, of Port St. Lucie, and said he was killed in shootout with SWAT officers.

• Shooting rampage kills 50, injures 53 at Florida nightclub
• Why mass shootings are 'an exceptionally American problem'

The previous deadliest mass shooting in the U.S. was the 2007 attack at Virginia Tech, in which a student killed 32 people before killing himself.

The worst peacetime mass shooting in the world remains the attack by Anders Behring Breivik, who set off a bomb in downtown Oslo and opened fire at a youth camp, killing 77 people. The self-styled anti-Muslim militant admitted both attacks.

Here's a closer look at the worst mass shootings in U.S. history:

32 killed at Virginia Tech in Blacksburg, Virginia, on April 16, 2007. The shooter was 23-year-old student Seung-Hui Cho, who took his own life.

27 killed at Sandy Hook Elementary in Newtown, Conn., on Dec. 14, 2012, including 20 children from a Grade 1 classroom and seven adults. Adam Lanza, 20, who had earlier murdered his mother, killed himself at the scene.

23 killed at Luby's Cafeteria in Killeen, Texas, on Oct. 16, 1991. George Hennard, 35, drove his pickup truck through the wall of the cafeteria, then shot and killed 23 people before dying by suicide.

21 killed at a McDonald's in San Ysidro, Calif., on July 18, 1984. James Huberty, 41, shot and killed 21 people in the restaurant before being killed by police.

18 killed at University of Texas, in Austin, on Aug. 1, 1966. Charles Joseph Whitman, a student at the university and former U.S. Marine, climbed a tower on campus and gunned down 16 people. He also killed his wife and mother and was later shot by police.

14 killed at the Inland Regional Center in San Bernardino, Calif., on Dec. 2, 2015. Syed Rizwan Farook and wife, Tashfeen Malik, who had declared allegiance to ISIS, shot and killed 14 people at an office holiday party before being killed by police.

14 killed at a post office in Edmond, Okla., on Aug. 20, 1986. Patrick Henry Sherrill, 44, a worker at the post office, killed 14 coworkers before dying by suicide.

13 killed at Columbine High School, Littleton, Colo., on April 20, 1999. Students Eric Harris, 18, and Dylan Klebold, 17, stormed the school, killing 12 classmates, one teacher and themselves. They also wounded 23 others.

13 killed at the Fort Hood military based near Killeen, Texas, on Nov. 5, 2009. Army psychiatrist Nidal Hasan killed 13 people and injured 30 before being shot. He lived, though, but was paralyzed. Hasan was sentenced to death but he has yet to be executed.

13 killed while attending a citizenship class at an immigration centre in Binghamton, N.Y., on April 3, 2009. Jiverly Antares Wong, a Vietnamese immigrant, shot 13 and wounded four before killing himself.

13 killed in the Wah Mee gambling club, in Seattle, Wash., on. Feb. 18, 1983. Three men bound, robbed and murdered 13 people and injured one man, who eventually testified against them in court. Kwan Fai "Willie" Mak, Wai-Chiu "Tony" Ng and Benjamin Ng were convicted of the crime.