Pedestrians in lower Manhattan watch smoke billow from New York's World Trade Center on Tuesday, Sept. 11, 2001.
A person falls from the north tower of New York's World Trade Center as another clings to the outside, left, while smoke and fire billow from the building.
Thick smoke billows into the sky from the area behind the Statue of Liberty, lower left, where the World Trade Center was.
Fire and smoke billows from the north tower of New York's World Trade Center.
Smoke billows through buildings in Manhattan as seen from Brooklyn after the collapse of New York's World Trade Center.
Pedestrians on Pierrepont Place in the Brooklyn borough of New York, watch as smoke billows from the remains of the World Trade Center in New York.
Firefighters work beneath the destroyed mullions, the vertical struts, of the World Trade Center in New York.
People walk over New York's Brooklyn Bridge from Manhattan to Brooklyn following the collapse of both World Trade Center towers on Sept. 11, 2001.