The sun rises over the Flight 93 Memorial on Sunday, Sept. 11, 2011, the tenth anniversary of the 9/11 attacks.

Mounted police patrol the hillside over the Flight 93 Memorial before it's official dedication ceremony on Saturday, Sept. 10, 2011.

Robin Scheppner of Erie, Pa., covers her heart during the National Anthem at the Flight 93 Memorial site on the 10th anniversary of the 9/11 attacks on Sunday, Sept. 11, 2011.

Shane Fenstermaker, whose aunt Loraine Bay, a stewardess on Flight 93, was killed on 9/11, watches the Flight 93 Memorial dedication ceremony on Sept. 10, 2011. Fenstermaker's tattoo is a remembrance of Bay.

President Barack Obama and first lady Michelle Obama pause after setting a wreath next to the Memorial Wall after the 9/11 memorial service at the Flight 93 Memorial on Sunday, Sept. 11, 2011.

United flight attendant Silja Kaude-Kelly of Brielle, N.J., touches the engraved name of flight attendant Deborah Jacobs Welsh while standing with her son, Christian Kelly, 16, at the Flight 93 Memorial on Saturday, Sept. 10, 2011. Kaude-Kelly formerly was based for United in Newark, N.J., and knew the attendants working on Flight 93.

A woman walks along the Flight 93 Memorial Wall, stopping to touch each name, on Saturday, Sept. 10, 2011.

Lyra Nacke, 3, walks past the Memorial Wall as family of the passengers of Flight 93 are given time to approach the wall before its opening to the public during the Flight 93 Memorial official dedication ceremony on Saturday, Sept. 10, 2011.

Lesa Roberts of Little Orleans, Md., takes a close look at the newly unveiled Memorial Wall at the Shanksville Flight 93 Memorial site on Sept. 10, 2011.

Volunteers light thousands of candles at the Flight 93 Memorial on Saturday, Sept. 10, 2011.

People stand silhouetted against the Flight 93 Memorial Wall on Saturday, Sept. 10, 2011.