Survivors of the terrorist attacks on the World Trade Center make their way through smoke, dust and debris on Fulton Street, about a block from the collapsed towers, Sept. 11, 2001

Ash covers a street in downtown New York City after the collapse of the World Trade Center on Sept. 11, 2001.

Broken windows in the vaulted roof of the Winter Garden, left, and the smashed facade of World Financial Center following the collapse of the World Trade Center, Sept. 27, 2001

Pedestrians on the waterfront in Brooklyn look across the East River to the burning World Trade Center towers on Sept. 11, 2001.

The twin towers of the World Trade Center burn behind the Empire State Building, Sept. 11, 2001

Smoke, flames and debris erupt from one of the World Trade Center towers as a plane strikes it on 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

Smoke spews from a tower of the World Trade Center on Sept. 11, 2001, after two hijacked airplanes hit the twin towers in a terrorist attack on New York City