In this 11 September 2001 file photo, a jet airliner nears one of the World Trade Center towers in New York.
An injured man waits for help as others take refuge in a bank near the World Trade Center towers on 11 September 2001, in New York.
James Bahn, foreground, and Irena Musial watch from a building rooftop on Greenwich St. in New York on Wednesday, 12 September 2001 as the street below is filled with rescue workers and equipment.
Ash from the World Trade Center terrorist attack covers an office across the street from the site on Thursday, 20 September 2001, in New York.
A firemen walks through the destroyed lobby of the World Financial Center near the World Trade Center in New York, on 12 September, 2001.
An ambulance, covered with debris, is on fire after the collapse of the first World Trade Center Tower on 11 September, 2001 in New York.
People run as the top of one of the World Trade Center towers collapses after two planes crashed into the North and South towers on 11 September 2001, in New York.
Rubble and ash fill lower Manhattan streets after two hijacked airplanes were flown into the twin towers of the World Trade Center in New York, on Tuesday, 11 September 2001.
An office filled with dust and debris has a view of the wreckage of the World Trade Center on 25 September 2001 in New York. Search and rescue efforts continued in the aftermath of the 9/11 terrorist attacks.
People flee the scene near New York's World Trade Center after terrorists crashed two planes into the towers on Tuesday, 11 September 2001.
Dust and debris cover the dishes and silverware on a table in an apartment in Battery Park City on Sunday, 23 September 2001, in New York.
People run from the collapse of the World Trade Center towers in New York, on Tuesday, 11 September 2001 after terrorists flew two hijacked airplanes into the North and South towers.
Rubble covers the tracks of the New York City subway's #1 and #9 lines in the Cortlandt Street station under the World Trade Center, in this undated photo made available in New York, on Friday, 28 September 2001.
People hang out of broken windows of the North Tower of the World Trade Center after a terrorist attack in New York on the morning of 11 September 2001.
This photo taken on 11 September 2001 shows mannequins on the floor of the Brooks Brothers' shop in New York near the World Trade Center after the twin towers collapsed. The store had been turned into a makeshift mortuary.
Emergency workers help a women after she was injured in the terrorist attack on the World Trade Center in New York, on 11 September 2001.
Destroyed mullions, the vertical struts which once faced the soaring outer walls of the World Trade Center towers, are all that is left behind a dust covered bus and subway entrance, after a terrorist attack on the twin towers of lower Manhattan on Tuesday, 11 September 2001.
Dust and ash cover toys in a child's bedroom in the apartment of Jerome and Joelle Bonnouvrier at 47 West Street, near the World Trade Center site on Wednesday, 19 September 2001.
Pedestrians on Beekman St. flee the area of the collapsed World Trade Center in lower Manhattan following a terrorist attack on the New York landmark on Tuesday, 11 September 2001.