Pentagon 9/11 Memorial (17 images)

U.S. President George W. Bush and First Lady Laura Bush participate in a wreath laying ceremony on the 5th anniversary of the September 11 terrorist attacks at the Pentagon in Arlington, Va., on September 11, 2006. (UPI Photo/Roger L. Wollenberg)

Jim Laychak, President of the Pentagon Memorial Fund, gives an update on the construction of Pentagon Memorial Park, at the Pentagon in Arlington, Virginia on September 7, 2007. The memorial, which is scheduled to be completed by September 11, 2008, honors the victims of the 9/11 terrorist attacks on the Pentagon. (UPI Photo/Kevin Dietsch)

Members of the military and civilians participate in the Pentagon's September 11th Wreath Laying Observance in Arlington, Virginia, on September 11, 2007. (UPI Photo/Roger L. Wollenberg)

U.S. President George W. Bush and First Lady Laura Bush sign the guest book at the Pentagon on the 5th anniversary of the September 11 terrorist attacks in Arlington, Va., on September 11, 2006. (UPI Photo/Roger L. Wollenberg)