PHOTOS: Remembering the terrorist attacks of 9/11

At least 1,000 family members, survivors, rescuers and officials were gathered as the ceremony at the World Trade Center began with a moment of silence and tolling bells. Then, relatives began reading out the names of the nearly 3,000 people killed when terrorist-piloted planes hit the trade center, the Pentagon and a Pennsylvania field, hurling America into a new consciousness of the threat of global terrorism.

United Airlines Flight 175 flies into the South Tower at 9:03 a.m. on Tuesday, Sept. 11, 2001.

A damaged tower collapses.

Firefighters raise a flag late in the afternoon of Sept. 11, 2001, in the wreckage of the World Trade Center towers.

People covered in dust walk over debris near the World Trade Center in New York.

A person jumps from the burning North Tower of the World Trade Center as another clings to the outside, left center.

Thick smoke billows behind the Statue of Liberty from where the towers once stood.

The remains of the World Trade Center.

(Suzanne Plunkett / Associated Press)
People flee as a World Trade Center tower collapses behind them.

(Doug Kanter / AFP/Getty Images)
A man stands in the rubble of the World Trade Center and calls out, asking if anyone needs help,

(Hubert Michael Boesl / AFP/Getty Images)
Smoke billows from the top floors of the World Trade Center towers.