Visitors to the Flight 93 National Memorial in Shanksville, Pa., participate in a sunset memorial service on Monday, Sept. 10, 2012. Tuesday marks the 11th anniversary of the Sept. 11,

 

              Visitors to the Flight 93 National Memorial in Shanksville, Pa., participate in a sunset memorial service on Monday, Sept. 10, 2012. Tuesday marks the 11th anniversary of the Sept. 11,
Visitors to the Flight 93 National Memorial in Shanksville, Pa., participate in a sunset memorial service on Monday, Sept. 10, 2012. Tuesday marks the 11th anniversary of the Sept. 11, 2001 terrorist attacks. (AP Photo/Gene J. Puskar)