US President Barack Obama (R), his wife Michelle Obama (2nd R), Former US President George W. Bush (2nd L) and his wife Laura Bush (L) salute as the national anthem is played during the 10th Anniversary commemoration of the September 11, 2001 attacks at the lower Manhattan site of the World Trade Center September 11, 2011 in New York. Families of victims are reflected in the bullet proof glass. AFP PHOTO/Stan HONDA (Photo credit should read STAN HONDA/AFP/Getty Images)