Parts of Los Angeles International Airport are shut down after a gunman opens fire. Take a look at some of the worst mass shootings in U.S. history.
Sept. 16, 2013: Authorities say military contractor Aaron Alexis gunned down 12 people and wounded eight others at the Washington Navy Yard before he was killed.
REUTERS/San Lorenzo soccer club/Handout
John F. Martin/General Motors
Sign up for Breaking News, Daily Headlines, Severe Weather Alerts & more!