More than 400 emergency personnel died rescuing people when the Twin Towers collapsed after hijackers flew two airplanes into the skyscrapers.
Those who attended the ceremony remembered the events of that day, the stories of heroism and the togetherness that America experienced in the days that followed.
"It's always hard, but humbling. I'm just mainly humbled to be around firefighters," said Bradley Burlingame, the brother of the pilot of American Airlines Flight 77, which crashed into the Pentagon.
As part of the tribute, helicopters did a flyover in the missing man formation.
"As individuals and as a collective, we have the power, the prescience and moral courage to make a difference. We should not underestimate the power of the individual choice. It has been said that we must not ignore the small daily differences, for often, they become the big difference that we cannot foresee," said Chief Millage Peaks of the Los Angeles City Fire Department said during a speech at the ceremony.
Peaks encouraged everyone to get involved and serve their communities in some way, even a little way in remembrance of 9/11.
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