Today marks the 13th year after two hijacked airplanes crashed into the Twin Towers in New York City.
Here is a look back at iconic photos from the tragic day.
Covered in smoke
Civilians flee as a tower of the World Trade Center collapses September 11, 2001 after two airplanes slammed into the Twin Towers.
Firefighter breaks down
A firefighter breaks down after the World Trade Center buildings collapsed September 11, 2001 after two hijacked airplanes slammed into the Twin Towers in a terrorist attack.
Early morning lights
Early morning light hits the smoke and wreckage of the World Trade Center September 13, 2001 in New York City, two days after the twin towers were destroyed when hit by two hijacked passenger jets.
See the rest of the iconic images below.