Those aboard "seized the moment" to ensure "the plane ... did not get to its target," likely in Washington, said Colin Powell, secretary of state when the attacks occurred.
Bells tolled for the 40 passengers and crew aboard the Newark, N.J.-to-San Francisco flight plane that crashed into a field near Shanksville, Pa., when the hostages attacked the hijackers.
"In place of fear," Powell said, "they found the courage to attack," sacrificing themselves to prevent a greater tragedy from occurring. "We are here to offer our profound thanks to their spirits."
Powell characterized phone calls passengers made to their loved ones as "treasured fragments" that helped piece together what happened on the flight that ended up in Somerset County, Pa.
Powell was joined by Interior Secretary Ken Salazar at the memorial. The speaker's podium held a placard reading, "Flight 93 Courage Remembered." Also attending were former Pennsylvania Gov. Tom Ridge, who was the first U.S. Secretary of Homeland Security, and retired Gen. Tommy Franks were among those at the site where the plane crashed.
"We must never forget what they did here as they struck the first blow in this battle against terrorism," said Powell, calling the passengers and crew "worthy successors" to heroes of previous wars going back to the American Revolution.