1. 9-11-2001

2. A jet airliner approaches the second World Trade Center tower in New York after another plane hit the first tower.

3. (AP photo by Carmen Taylor / September 11, 2001) A fireball explodes from one of the World Trade Center towers in New York after a jet airliner crashed into the building.

4. (AP photo by Amy Sancetta / September 11, 2001) The south tower of the World Trade Center begins to collapse after a terrorist attack on the New York landmark.

5. (AP photo by Richard Drew / September 11, 2001) A person jumps from the north tower of the World Trade Center as another clings to the outside (left) while smoke and fire billow from the building. Terrorists crashed two hijacked airliners into the New York landmark and brought down its twin towers.

6. (AP photo by Suzanne Plunkett / September 11, 2001) People run from the collapse of the World Trade Center in lower Manhattan after terrorists crashed two jet airliners into the twin towers.

7. (New York Times photo by Steffen Kaplan / September 11, 2001) Smoke billows over downtown Manhattan after the second tower of the World Trade Center collapsed in a terrorist attack with hijacked airplanes.

8. (AP photo by Graham Morrison / September 11, 2001) A firefighter moves through piles of debris at the site of the World Trade Center. About 300 New York firefighters exposed to smoke and dust from the disaster are now on medical leave for respiratory problems.

9. (AP photo by Alex Fuchs / September 11, 2001) The remains of the World Trade Center stand amid smoke and debris after the terrorist attack on the New York buildings.

10. (AP photo by Diane Bondareff / September 11, 2001) People flee the scene near New York's World Trade Center after terrorists crashed two planes into the towers in a coordinated series of attacks that brought down the twin 110-story towers.

11. (AP photo by Amy Sancetta / September 11, 2001) Pedestrians flee the area of the World Trade Center in lower Manhattan following a terrorist attack on the New York landmark.

12. (AP photo by Ernesto Mora / September 11, 2001) Two women hold each other as they watch the World Trade Center burn following a terrorist attack on the twin skyscrapers in New York.

13. (AP photo by Doug Mills / September 11, 2001) President Bush's Chief of Staff Andy Card whispers into the ear of the President, telling him about the planes crashing into the World Trade Center. Bush was visiting the Emma E. Booker Elementary School in Sarasota, Fla. President Bush

14. (Reuters photo by Larry Downing / September 11, 2001) A rescue helicopter flies over the damage to the Pentagon Building as fire fighters battle flames after American Airlines Flight 77 crashed into the U.S. military Headquarters outside of Washington. American Airlines

15. Firefighters hose down the twisted and smoldering remnants of one side of the Pentagon after American Airlines Flight 77 crashed into the Pentagon's west wall on the morning of Sept. 11, 2001.

16. (AFP/Getty photo by David Maxwell / September 11, 2001) Firefighters and emergency personnel look through the debris of United Airlines Flight 93 after it crashed on the morning of Sept. 11, 2001 near Shanksville, Pennsylvania. 40 victims were killed in the crash after passengers reportedly stormed the cockpit to thwart terrorists' plans to use that plane as a weapon like the others. United Airlines

17. (Tribune-Democrat photo by David Lloyd / September 11, 2001) Firefighters and emergency personnel investigate the scene of the fatal crash of United Airlines Flight 93 on the morning of Sept. 11, 2001 near Shanksville, Pennsylvania. 40 victims were killed in the crash after passengers reportedly stormed the cockpit to thwart terrorists' plans to use that plane as a weapon like the others. United Airlines