ARLINGTON, VA – NOVEMBER 11: Visitors watch in silence as soldiers from the 3rd U.S. Infantry Regiment, called the “Old Guard,” perform the changing of the guard at the Tomb of the Unknowns before a Veterans Day full honor ceremony at Arlington National Cemetery November 11, 2011 in Arlington, Virginia. President Barack Obama later delivered remarks at the cemetery amphitheater after laying a wreath at the tomb. (Photo by Chip Somodevilla/Getty Images)