World Trade Explosion
Smoke, flames and debris erupts from one of the World Trade Center towers as a plane strikes it Tuesday, Sept. 11, 2001. The first tower was already burning following a terror attack minutes earlier. Terrorists crashed planes into the two buildings and collapsed both towers. (AP Photo/Chao Soi Cheong)

Panic Run
Pedestrians flee the area of the World Trade Center as the center's south tower crashes following a terrorist attack on the New York landmark Tuesday, Sept. 11, 2001. (AP Photo/Amy Sancetta)

Getting Treatment
An emergency worker treats a victim near the World Trade Center in New York after terrorists crashed two airliners into the twin 110-story towers Tuesday, Sept. 11, 2001. Both towers collapsed following the crashes. (AP/Photo/Amy Sancetta)

Palestinian Celebration
A group of children near east Jerusalem's Old City wave Palestinian flags and chant anti-U.S slogans as they react to the news of a terrorist attack on the World Trade Center in New York Tuesday Sept. 11, 2001. (AP Photo/Lefteris Pitarakis)

After learning of the World Trade Center attacks, Susie Kaltenbacher, right, weeps as her husband, Kent Kaltenbacher, comforts her at the Reno Tahoe Airport in Reno, Nev., Tuesday, Sept. 11, 2001. Susie's brother works at the Trade Center and she is unsure of his welfare. The Anchronge, Alaska, couple became stranded after all flights across the country were cancelled following the attacks in New York and Washington. (AP Photo/Reno Gazette-Journal, Marilyn Newton)

Emergency Call
An unidentified air hostess dials a cell phone at the Albuquerque Sunport on Tuesday, Sept. 11, 2001, after learning about the terrorist attack on the World Trade Center. All commercial flights in the United States were grounded. (AP Photo/Pat Vasquez-Cunningham)