Hundreds meeting for 9/11 anniversary in Shanksville, Pa.

The 40 passengers and crew members of a plane that crashed in western Pennsylvania after it was hijacked during the September 11 terror attacks have been honored with a reading of names and tolling of bells.

Hundreds have been taking part in the annual service at the Flight 93 National Memorial in Shanksville as ceremonies have also been taking place Sunday in New York and Washington, D.C.

CLICK HERE TO WATCH President Obama speaking to hundreds of service members, and relatives and survivors of the 9/11 attack on the Pentagon.

CLICK HERE TO WATCH various scenes from NY: moment of silence, bells tolling, dignitaries, politicians, some of the 2,977 names read.

For the first time, the Shanksville ceremony is being held outside the visitor center that opened last year rather than at the granite mall that runs along the crash site.

On the eve of 15th anniversary, people paid their respects at the wall of names that bears the names of the passengers and crew of United Airlines flight 93 who tried to regain control of the aircraft after it was hijacked by the terrorists.

As dusk set in, forty candle lanterns were carried to the wall. Each was placed below the name of a passenger or crew member. Everyone aboard was killed when the plane crashed.

Flight 93 had been headed from Newark to San Francisco when the hijackers took over.

They apparently had planned to crash the plane into the White House or the Capitol building.

Conversations from the flight's final minutes indicate the passengers had some idea of what was happening.

On the words "Let's roll," they stormed the cockpit. The plane went down shortly after that.