10 years later: Remembering 9/11 at ground zero

Robert Peraza, who lost his son Robert David Peraza, pauses at his son's name at the North Pool of the 9/11 Memorial during tenth anniversary ceremonies at the site of the World Trade Center on Sept. 11, 2011, in New York City. New York City and the nation are commemorating the 10th anniversary of the 9/11 terrorist attacks on lower Manhattan which resulted in the deaths of 2,753 people after two hijacked planes crashed into the World Trade Center. Security has been heightened in both New York City and Washington D.C. following a possible car bomb threat.

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A view of the 9/11 memorial in New York, Sept. 11, 2011, during the official ceremony marking the 10th anniversary of the terrorist attack. In the Sept. 11, 2001 attacks, al Qaeda hijackers crashed passenger planes into the World Trade Center in New York and the Pentagon in Washington, while a fourth jet crashed in Shanksville, Pa.

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A single rose lies above one of the names inscribed on a wall at the Sept. 11 memorial in New York, Sept. 11, 2011, as families who lost loved ones in the World Trade Center attacks joined others to make the 10th anniversary of those attacks.

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Lt. Brian Malone, who lost many co-workers in the NY Fire Department, takes a moment beside the south memorial pool during tenth anniversary ceremonies of the September 11, 2001 terrorist attacks at the World Trade Center site September 11, 2011 in New York City. New York City and the nation are commemorating the tenth anniversary of the terrorist attacks which resulted in the deaths of nearly 3,000 people after two hijacked planes crashed into the World Trade Center, one into the Pentagon in Arlington, Virginia and one crash landed in Shanksville, Pennsylvania.

Engraved names at the South Pool are decorated at the National 9/11 Memorial during the tenth anniversary ceremonies of the September 11, 2001 terrorist attacks at the World Trade Center site, September 11, 2011 in New York City.

A woman touches the memorial wall on the North Tower reflecting pool of the 9/11 Memorial on Sept. 11, 2011 in New York as the 10th anniversary of the 9/11 attacks is observed.

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At the memorial pool, Vasantha Velamuri mourns at the sight of her husband's name, Sankara Sastry Velamuri, who died in the World Trade Center, during ceremonies at the World Trade Center site September 11, 2011 in New York City.

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A young boy points to a name on the wall at the Sept. 11 memorial during the 10th anniversary observance of the terrorist attacks on the World Trade Center, Sunday, Sept. 11, 2011 in New York.

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An image of the World Trade Center twin towers is taped onto the bronze plaques that bear the names of the victims of the September 11 terror attacks that surround the perimeter of the 9/11 Memorial pool during the tenth anniversary ceremonies of the September 11, 2001 terrorist attacks at the World Trade Center site, September 11, 2011 in New York City.

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Nancy Gregory hugs her sons, Carl (left) and Gregory, as they pay their respects to her husband, firefighter Ken Kumpel, at the National 9/11 Memorial during the tenth anniversary ceremonies of the September 11, 2001 terrorist attacks at the World Trade Center site, September 11, 2011 in New York City.

Visitors to the National 9/11 Memorial at ground zero in New York City trace the names of victims of the September 11, 2011 terrorist attacks, Sunday, September 11, 2011.

A woman cries while looking at the names inscribed at the North Pool of the 9/11 Memorial during tenth anniversary ceremonies at the site of the World Trade Center Sept. 11, 2011, in New York.

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Families line up against the wall of the south memorial pool at the Sept. 11 memorial during 10th anniversary ceremonies commemorating the 2001 terrorist attacks on the World Trade Center, Sunday, Sept. 11, 2011, in New York.

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Jose Valdez and his friend Mary Santiago hug as they look over the name of Valdez' sister, Mayra Valdes Rodriguez, at the National 9/11 Memorial during the tenth anniversary ceremonies of the September 11, 2001 terrorist attacks at the World Trade Center site, September 11, 2011 in New York City.

Two military personnel stand next to the North Pool of the 9/11 Memorial during the tenth anniversary ceremonies of the September 11, 2001 terrorist attacks at the World Trade Center site, September 11, 2011 in New York City.

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U.S. flags stand among a list of victims' names on a memorial pool during tenth anniversary ceremonies of the September 11, 2001 terrorist attacks at the World Trade Center site September 11, 2011 in New York City.

Mourners pay their respects at the north pool at the National September 11 Memorial during a ceremony marking the 10th anniversary of the attacks at World Trade Center, Sunday, Sept. 11, 2011 in New York.

Keri McMorrow, 7, visits the memorial pool where her uncle's name is engraved, during tenth anniversary ceremonies of the September 11, 2001 terrorist attacks at the World Trade Center site September 11, 2011 in New York City. James Joseph Kelly worked for Cantor Fitzgerald.

Family members who lost loved ones attend the memorial during 10th anniversary ceremonies of the September 11, 2001 terrorist attacks at the World Trade Center site September 11, 2011 in New York City.

Family and friends of victims look over the names on the 9/11 Memorial during the tenth anniversary of the September 11, 2001 terrorist attacks at the World Trade Center site, September 11, 2011 in New York City.

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Family and friends of victims gather at the edge of the 9/11 Memorial during the tenth anniversary of the September 11, 2001 terrorist attacks at the World Trade Center site, September 11, 2011 in New York City.

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A man is searched before entering the World Trade Center site for the 10th anniversary of the terrorist attacks on lower Manhattan on September 11, 2001 in New York City.

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Family members and friends of the victims of the terrorist attacks enter Memorial Plaza to pay their respects during the tenth anniversary ceremonies of the September 11, 2001 terrorist attacks at the World Trade Center site, September 11, 2011 in New York City.

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People carry portraits of their dead relatives as they gather at the 9/11 memorial in New York, Sept. 11, 2011, during the official ceremony marking the 10th anniversary of the terrorist attacks. In the Sept. 11, 2001 attacks, al Qaeda hijackers crashed passenger planes into the World Trade Center in New York and the Pentagon in Washington, while a fourth jet crashed in Shanksville.

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People observe a moment of silence during ceremonies at the World Trade Center site for the 10th anniversary of the terrorist attacks on lower Manhattan on Sept. 11, 2001 in New York City. New York City and the nation are commemorating the 10th anniversary of the terrorist attacks on lower Manhattan which resulted in the deaths of 2,753 people when two hijacked planes crashed into the World Trade Center. Security has been heightened in both New York City and Washington D.C. following a terrorist threat about a car bomb.

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The commemoration ceremony at the National September 11 Memorial on Sept. 11, 2011 at ground zero in New York City as the U.S. remembers the 9/11 attacks on the 10th anniversary.

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Former U.S. President George W. Bush and President Barack Obama visit the 9/11 memorial on Sept. 11, 2011 in New York on the 10th anniversary of the 9/11 attacks.

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President Barack Obama walks past a reflecting pool near the bronze-etched names of the victims of the terrorist attack 10 years ago with his wife Michelle, and former President George W. Bush and his wife, Laura, as they arrive for the ceremony marking the 10th anniversary of the attacks, Sept. 11, 2011 in New York. Two reflecting pools built over the towers' footprints, part of a Sept. 11 memorial that was to open later in the day for relatives of the victims.

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President Barack Obama and first lady Michelle Obama, former President George W. Bush and former first lady Laura Bush bow their heads during a moment of silence at the Sept. 11 10th Anniversary Commemoration Ceremony at Ground Zero in New York, Sept. 11, 2011.

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President Barack Obama, right, reads a passage of the Bible's Psalm 46 during the 10th Anniversary Commemoration Ceremony at Ground Zero in New York, Sept., 11, 2011 in New York. With Obama from left to right are former first lady Laura Bush, former President George W. Bush, and first lady Michelle Obama.

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A U.S. flag recovered from the 9/11 attacks is displayed by New York City Police officers and firefighters during the ceremony marking the 10th anniversary of the terrorist attack. In the Sept. 11, 2001 attacks, al Qaeda hijackers crashed passenger planes into the World Trade Center in New York and the Pentagon in Washington, while a fourth jet crashed in Shanksville, Pa.

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New York police and firefighters and Port Authority police salute during the singing of the Star Spangled Banner at one of the entrances of 9/11 Memorial Plaza during the tenth anniversary ceremonies of the Sept. 11, 2001 terrorist attacks at the World Trade Center site, Sept. 11, 2011 in New York City. New York City and the nation are commemorating the tenth anniversary of the terrorist attacks on lower Manhattan which resulted in the deaths of 2,753 people after two hijacked planes crashed into the World Trade Center.

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Members of the New York Police Department, New York Fire Department, and Port Authority line up for a preparation exercise before the tenth anniversary ceremonies at the site of the World Trade Center on September 11, 2011 in New York City. New York City and the nation are preparing to commemorate the 10th anniversary of the 9/11 terrorist attacks on lower Manhattan which resulted in the deaths of 2,753 people after two hijacked planes crashed into the World Trade Center. Security has been heightened in both New York City and Washington D.C. following a possible car bomb threat.

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Port Authority Police officers observe a moment of silence during the tenth anniversary ceremonies of the Sept. 11, 2001 terrorist attacks at the World Trade Center site, Sept. 11, 2011 in New York City. New York City and the nation are commemorating the tenth anniversary of the terrorist attacks on lower Manhattan which resulted in the deaths of 2,753 people after two hijacked planes crashed into the World Trade Center.

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A line of bagpipers walks towards the stage past the North Pool at the tenth anniversary ceremonies of the Sept. 11, 2001 terrorist attacks at the World Trade Center site Sept. 11, 2011 in New York City. New York City and the nation are commemorating the tenth anniversary of the terrorist attacks which resulted in the deaths of nearly 3,000 people after two hijacked planes crashed into the World Trade Center, one into the Pentagon in Arlington, Va. and one crash landed in Shanksville, Pa.

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Visitors hug near a 9/11 Memorial pool during the tenth anniversary ceremonies of the Sept. 11, 2001 terrorist attacks at the World Trade Center site, Sept. 11, 2011 in New York City. New York City and the nation are commemorating the tenth anniversary of the terrorist attacks on lower Manhattan which resulted in the deaths of 2,753 people after two hijacked planes crashed into the World Trade Center.

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Family members read names of victims at the 9/11 Memorial during the tenth anniversary ceremonies of the September 11, 2001 terrorist attacks at the World Trade Center site, September 11, 2011 in New York City.

Madhu Narula, of Kings Park, N.Y., reacts after hearing the name of her daughter, Manika Narula, pictured on shirt below, among the names of victims of 9/11, read during a ceremony marking the 10th anniversary of the attacks at the National September 11 Memorial at the World Trade Center site, Sunday, Sept. 11, 2011, in New York.

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Iba Cedeno holds a photograph of her partner Catherine Theresa Smith at the 9/11 Memorial on Sept. 11, 2011 in New York as the U.S. marks the 10th Anniversary of the Sept. 11, 2001 attacks.

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Judy Busta of Protivin, Iowa, stands before ribbons of remembrance at St. Paul's Chapel near ground zero Sept. 11, 2011 as she came to New York to commemorate the 10th anniversary of the attacks at the World Trade Center.

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People arrive to the ceremony marking the 10th anniversary of the Sept. 11 terrorist attacks on the World Trade Center, outside ground zero site in New York, Sept. 11, 2011.

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The names of those killed in the 9/11 attacks glow along the edge of the South Pool of the 9/11 Memorial before the tenth anniversary ceremonies of the Sept. 11, 2001 terrorist attacks at the World Trade Center site, Sept. 11, 2011 in New York City. New York City and the nation are commemorating the tenth anniversary of the terrorist attacks on lower Manhattan which resulted in the deaths of 2,753 people after two hijacked planes crashed into the World Trade Center.

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A firefighter plays taps at the conclusion of a ceremony marking the tenth anniversary of the September 11, 2001 terrorist attacks, at the World Trade Center site, September 11, 2011 in New York City.

One World Trade Center towers over the site, Sunday, Sept. 11, 2011 in New York. A decade has passed since the Sept. 11 attacks when terrorists crashed hijacked planes into the World Trade Center and the Pentagon, and a fourth plane crashed into a field in rural western Pennsylvania.

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The World Trade Center is aglow in light, Sunday, Sept. 11, 2011 in New York. One World Trade Center is left, 4 World Trade Center is right, and the memorial waterfalls are lower center and lower right.

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Christine Corday puts final touches on the name panels on the north pool at the National September 11 Memorial before a ceremony marking the 10th anniversary of the attacks at the World Trade Center site Sunday, Sept. 11, 2011 in New York.

On the night before the tenth 9/11 anniversary, two beams of light, titled "Tribute in Light" are projected into the sky in memorial of the Sept. 11, 2001 attacks on the World Trade Center Buildings. New York City and the nation are marking the tenth anniversary of the terrorist attacks on lower Manhattan which resulted in the deaths of 2,753 people at the World Trade Center.

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