A man walks through the Empty Sky memorial at sunrise across from New York's Lower Manhattan and One World Trade Center in Liberty State Park in Jersey City, New Jersey, Sept. 11, 2013.
Civil War re-enactor Cpl. Robert Fuller Houston with the 3rd Regiment Infantry, lowers his head during a prayer at a ceremony, Sept. 11, 2013, marking the 12th anniversary of the 9/11 terrorist attacks at the Betsy Ross House in Philadelphia.
The sun reflects off the stainless steel wall of the "Empty Sky" memorial to New Jersey's victims of the Sept. 11, 2001 terrorist attacks, Sept. 11, 2013, in Jersey City, N.J.
Detroit Fire Department Lt. Gerod Funderburg rings a bell during a ceremony in Detroit, Sept. 11, 2013, marking the 12th anniversary of the 9/11 terrorist attacks.