A bell ringing ceremony and a helicopter flyover took place at the Frank Hotchkin Memorial Training Center in Elysian Park.
"Once each year washes a little more of the immediacy away, but it doesn't ever heal the wound," said Mayor Eric Garcetti.
Bells rang as first responders united to honor their fellow first responders lost on Sept. 11, 2001.
"We gather together today to remember our dead and to inspire our living," said Los Angeles Police Chief Charlie Beck.
The Frank Hotchkin Memorial Training Center now houses 23 tons from the South Tower of the World Trade Center. Back in 2001, Los Angeles sent 72 firefighters to Ground Zero to help in the response.
"It was overwhelming in the sense of the magnitude of the incident itself and everywhere we went," said Bat. Chief Steve Hissong, who was sent to New York to help following the attacks.
A ceremony was also held at Fire Station 88 in Sherman Oaks, where pieces of the World Trade Center and the Pentagon stand as part of a memorial. All of the names of the victims and first responders killed in the tragedy are on display.
Before Wednesday night's baseball game at Dodger Stadium, a 9/11 memorial ceremony paid tribute to firefighters and law enforcement officers.
The event brought back vivid memories for Robert Schiavone, who was a New York City firefighter at the time of the attack on the World Trade Center. Now, he's a deputy with the Los Angeles County Sheriff's Department.
"You just walked around in total amazement. It was something like out of a movie. It just didn't look real -- gaping holes in buildings, it was a lot of smoke, dust," said Schiavone.
Schiavone is proud of the way New York and the nation rallied during the dark days following the attack.
"People cheering you on, people having candlelight vigils, everybody was so nice to each other," said Schiavone.