9/11: Then and now

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

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NYC Skyline 2011

The New York City skyline from the Empire State Building — Gordon Donovan/CBSNews.com

The Empire State Building dominates the New York skyline on Sept. 5, 2011.

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Brooklyn Bridge 2001

Women wearing dust masks flee across New York's Brooklyn Bridge from Manhattan to Brooklyn following the collapse of both World Trade Center towers on Sept. 11, 2001.

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Brooklyn Bridge 2011

Pedestrians cross the Brooklyn Bridge, with the lower Manhattan skyline in the background, on Sunday, Sept. 4, 2011.

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Beekman Street 2001

Pedestrians on Beekman Street flee the area of the collapsed World Trade Center towers in lower Manhattan following the terrorist attacks on the New York landmarks on Sept. 11, 2001.

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Beekman Street 2011

A couple passes the parking garage on Beekman Street in New York, Sunday, Sept. 4, 2011, the area that was choked by smoke and dust after the collapse of the World Trade Center towers in 2001.

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Park Row 2001

south tower collapses as people run to safety — AP Photos/Amy Sancetta

Pedestrians on Park Row flee the area of the World Trade Center as the center's south tower collapses following the terrorist attack on the New York landmark on Sept. 11, 2001.

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Park Row 2011

Traffic heads north towards the Brooklyn Bridge on New York's Park Row, Sunday, Sept. 4, 2011.

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Fulton Street 2001

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

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Fulton Street 2011

People make their way along Fulton Street along St. Paul's Church near the World Trade Center site, Sunday, Sept. 4, 2011.

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Murray Street 2001

debris from one of the crashed airliners, — AP Photo/Chris Kline

A piece of debris, possibly from one of the crashed airliners, lies on the corner of Murray Street in lower Manhattan near the World Trade Center site in New York on Sept. 11, 2001.

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Murray Street 2011

Murray St. and Church St. — Gordon Donovan/CBSNews.com

All debris has been cleared away on the corner of Murray Street in lower Manhattan near the World Trade Center site, Sunday, Sept. 4, 2011.

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Cortlandt Street 2001

With the skeleton of the World Trade Center twin towers in the background, New York City firefighters work amid debris on Cortlandt Street after the terrorist attacks on Sept. 11, 2001.

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Cortlandt Street 2011

Looking down Cortlandt Street in New York on Sunday, Sept. 4, 2011, just steps from where the World Trade Center stood.

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Church and Dey Streets 2001

Subway entrance on Dey Street — AP Photo

A subway entrance is covered in debris at the intersection of Church and Dey Streets after the World Trade Center collapse in New York City on Sept. 11, 2001.

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Church and Dey Streets 2011

Church St. and Dey St. subway stop — Gordon Donovan/CBSNews.com

The new subway station on Church and Dey Streets nearly 10 years later, as construction continues across the street at the World Trade Center site, Sunday, Sept. 4, 2011.

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Greenwich Street 2001

Greenwich Street covered in debris — AP Photo

Debris from the collapse of the World Trade Center towers covers Greenwich Street near Rector Street on Sept. 11, 2001.

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Greenwich Street 2011

Greenwich St. and Rector St. — Gordon Donovan/CBSNews.com

The intersection of Greenwich and Rector Streets, looking north to where 2 World Trade Center once stood, Sunday, Sept. 4, 2011.

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Trinity Church 2001

Ash covers gravestones in Trinity Church on Sept. 11, 2001 after the attacks on the nearby World Trade Center towers in New York.

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Trinity Church 2011

The courtyard and graveyard at Trinity Church in Lower Manhattan nearly 10 years after the attacks on the Twin Towers, Sunday, Sept. 4, 2011.

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Brooklyn 2001

The south tower begins to collapse as smoke billows from both towers of the World Trade Center, in New York, Sept. 11, 2001.

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Brooklyn 2011

The skyline of lower Manhattan across the East River near the Brooklyn Bridge, Sunday, Sept. 4, 2011.

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Fulton Street 2001

People run from a cloud of debris from the collapse of a World Trade Center tower in New York on Tuesday, Sept. 11, 2001.

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Fulton Street 2011

Construction is still underway on Fulton Street looking west towards the where the towers of the World Trade Center once stood, Sunday, Sept. 4, 2011.

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West Street 2001

The north tower of New York's World Trade Center collapses after being struck by hijacked American Airlines Flt. 11 on Sept. 11, 2001.

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West Street 2011

The skyline of lower Manhattan Sunday, Sept. 4, 2011, where the towers of the World Trade Center stood is still under going construction all around the area.

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Liberty Street 2001

Firefighters and urban rescue workers work at the site of collapsed World Trade Center towers after the terrorist attacks in New York, on Sept. 19, 2001.

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Liberty Street 2011

construction of World Trade Center — Gordon Donovan/CBSNews.com

The view of the construction of new buildings where the World Trade Center once stood continues Sunday, Sept. 4, 2011.

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