On this 24th anniversary of the Sept. 11 attacks, New Yorkers are once again pausing to remember the nearly 3,000 lives lost and the heroes who answered the call that day.

This morning, FDNY firefighters from Brooklyn’s Battalion 57 will carry American and FDNY flags across the Brooklyn Bridge in honor of the 23 members they lost in the attacks. The procession will lead to the Co-Cathedral of St. Joseph in Prospect Heights, where Bishop Robert Brennan will celebrate a Mass at noon.

The tradition, organizers say, is about more than honoring the past. It’s a way to bring together families, first responders, and neighbors who believe it’s vital to never forget.

Across the borough, communities are holding their own ceremonies:

At Green-Wood Cemetery, more than 100 people laid to rest there are being honored with a reading of names and the “Tribute in Light,” two beams rising into the night sky as a reminder of the Twin Towers.

For many New Yorkers, the lights remain one of the most powerful symbols of remembrance. “I look forward to the beacons that go up into the sky,” said Diana Granat of Downtown Brooklyn. “I would really miss them if they didn’t have them. I come out when they turn them on and I try to catch them before they turn them off as well.”

The Brooklyn Bridge procession steps off at 11 a.m., with the Mass at noon.