Photos: A Nation Remembers Sept. 11

Shanksville, Pa., Sept. 10, 2011
Former First Lady Laura Bush, former President George W. Bush, former President Bill Clinton, Jill Biden and her husband Vice President Joe Biden, from left, stand in front of the Flight 93 National Memorial at the conclusion of ceremonies marking the 10th anniversary of the 9/11 attack in Shanksville, Pa., on Sept. 10, 2011.

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