Plumes of smoke pour from the World Trade Center buildings in New York Tuesday, Sept. 11, 2001. Planes crashed into the upper floors of both World Trade Center towers minutes apart Tuesday in a horrific scene of explosions and fires that left gaping holes
The south tower of the World Trade Center, left, begins to collapse after a terrorist attack on the landmark buildings in New York, Tuesday, Sept. 11, 2001. (AP Photo/Gulnara Samoilova)
Pedestrians flee the area of the World Trade Center as the center's south tower collapses following a terrorist attack on the New York landmark Tuesday, Sept. 11, 2001. (AP Photo/Amy Sancetta) ITALY OUT
The twin towers of the World Trade Center burn behind the Empire State Building in New York, Tuesday, Sept. 11, 2001. In a horrific sequence of destruction, terrorists crashed two planes into the World Trade Center and the twin 110-story towers collapsed.