Sept. 11

FILE - In this Sept. 13, 2001 file photo, an American flag flies over the rubble of the collapsed World Trade Center buidlings in New York. (AP Photo/Beth A. Keiser)

FILE - In this Wednesday, Sept. 12, 2001 file picture, firefighters and inspectors look over the damage to the Pentagon in Washington after a hijacked airliner crashed into the Department of Defense building on Tuesday. The dome of the United States Capitol is seen in the background. (AP Photo/Steve Helber)

Miriam Love embraces her daughter at Battery Park in New York Sunday afternoon Sept. 11, 2011. Three thousand flags were placed in the park to honor those who were killed in the terrorist attacks on September 11, 2001. (AP Photo Allen Otto/The Daily Texan)

Brinlee McCluskey, 9, bows her head in prayer as Rev. Steve Campbell of Pinelake Church in Flowood offers an invocation outside Reservoir Fire Department Station 1 in Flowood, Miss. on the tenth anniversary of the Sept. 11, 2001 terrorist attacks. on Sunday, Sept. 11, 2011. (AP Photo/The Clarion-Ledger, Joe Ellis)

FILE - In this Sept. 11, 2001 file photo, the south tower of the World Trade Center begins to collapse after a terrorist attack on the New York landmark. (AP Photo/Amy Sancetta)

FILE - In this Sept. 11, 2001 file photo, United Airlines Flight 175 approaches the south tower of the World Trade Center in New York shortly before collision as smoke billows from the north tower. (AP Photo/Carmen Taylor)

FILE - In this Tuesday, Sept. 11, 2001 file photo, the south tower starts to collapse as smoke billows from both buildings of the World Trade Center in New York. (AP Photo/Jim Collins)

FILE - This Tuesday, Sept. 11, 2001 file photo shows the impact site of American Airlines Flight 11 in the north tower of the World Trade Center in New York. A person stands at the bottom center of the tear in the building. (AP Photo/Amy Sancetta)

In this Sunday, Sept. 11, 2011 photo provided by Central Michigan University, students gather near Park Library on the Central Michigan University campus in Mount Pleasant, Mich., at 9:11 p.m., for a candlelight vigil honoring those who died in the Sept. 11, 2001 attacks. The volunteer center on campus organized the event and Stephanie Pocsi, a student staff member, left, reads a letter from Deborah Garcia, the wife of a victim. In the letter she thanks the students for the ongoing volunteer project honoring her husband David Garcia, who died in the attacks. (AP Photo/Central Michigan University, Peggy Brisbane)

FILE - In this Sept. 11, 2001 file photo, United Airlines Flight 175 collides into the south tower of the World Trade Center in New York as smoke billows from the north tower. (AP Photo/Chao Soi Cheong)

FILE - In this Tuesday, Sept. 11, 2001 file photo, people run from a cloud of debris from the collapse of a World Trade Center tower in New York. (AP Photo/Suzanne Plunkett)

FILE - In this Sept. 14, 2001 file photo, President George W. Bush embraces firefighter Bob Beckwith while standing in front of the collapsed World Trade Center buildings in New York as rescue efforts continue. (AP Photo/Doug Mills)

Coast Guard officers at Coast Guard base Kodiak salute as members of the base's fire department raise an American flag during a sunrise ceremony on Sunday, Sept. 11, 2011, in Kodiak, Alaska. The ceremony was held in honor of the people killed in the Sept. 11, 2011 terrorist attacks on the United States and involved the Coast Guard base's Ladder Tower 343 truck, a vehicle named in honor of the 343 New York City firefighters killed in the attack. (James Brooks/Kodiak Daily Mirror)

Zacharia Morris, 3, Bloomington, Ill., stands in respect of firefighters who lost their lives during the attacks of Sept. 11, as the Bloomington Fire Department sounded its sirens at noon at their Lee Street station, Sunday, Sept. 11, 2011. Morris' father, James, brought the boy to the station because his son had expressed interest in being a firefighter. (AP Photo/The Pantagraph, David Proeber)

FILE - In this Tuesday, Sept. 11, 2001 file picture, a person falls headfirst from the north tower of New York's World Trade Center. (AP Photo/Richard Drew)

FILE - In this Tuesday, Sept. 11, 2001 file photo, the south tower starts to collapse as smoke billows from both buildings of the World Trade Center in New York. (AP Photo/Richard Drew)

FILE - This undated aerial photo provided by the FBI shows damage caused by a hijacked airliner that crashed into the Pentagon in Washington on Sept. 11, 2001. (AP Photo/FBI)

FILE - In this Sept. 11, 2001 file photo, the twin towers of the World Trade Center burn behind the Empire State Building in New York. (AP Photo/Marty Lederhandler, File)

FILE - In this Tuesday, Sept. 11, 2001 file photo, Chief of Staff Andy Card whispers into the ear of President George W. Bush to give him word of the plane crashes into the World Trade Center, during a visit to the Emma E. Booker Elementary School in Sarasota, Fla. (AP Photo/Doug Mills)

FILE - In this Tuesday, Sept. 11, 2001 file photo, two women hold each other as they watch the World Trade Center burn following a terrorist attack on the twin skyscrapers in New York. (AP Photo/Ernesto Mora)

FILE - In this Sept. 11, 2001 file photo, people covered in dust walk over debris near the World Trade Center in New York. (AP Photo/Gulnara Samoilova)

Capt. Frank Beauvais of the Nampa Fire Dept., gives his son Charlie, 4, a kiss on the cheek in front of a salvaged piece of steel that was found in the ruins of the World Trade Center and unveiled at a First Responders Ceremony on Sunday, September 11, 2011 at the Nampa Fire Station in Nampa, Idaho. (AP Photo/Idaho Press-Tribune, Adam Eschbach) -Mandatory Credit-

FILE - In this Tuesday, Sept. 11, 2001 file photo, with the skeleton of the World Trade Center twin towers in the background, New York City firefighters work amid debris on Cortlandt St. after the terrorist attacks. (AP Photo/Mark Lennihan)