The Tunnel to Towers 5K Run & Walk took place Sunday. The course retraced the steps of FDNY firefighter Stephen Siller when he travelled through the Battery Tunnel to the Twin Towers on Sept. 11, 2001.

Antoine Morales, a firefighter in the Bronx, ran the race with his gear on. He said there was a point in the tunnel when the journey got tough, but he pushed through.

“When I got to the incline, just me thinking about that how the guys did it on 9/11, that gave me that extra push to keep going,” Morales said.

The Tunnel to Towers Foundation has organized the event for the past 21 years. The nonprofit helps family members of first responders and veterans by providing mortgage-free homes. At the run Sunday, many attendees were family members who lost someone and found support through the organization.

In 2002, the run started with 1,500 participants. Now, 21 years later, organizers say more than 30,000 people participated Sunday.

“It’s incredible the growth of it. But that’s what happens,” said Frank Siller, the chairman and CEO of the Tunnel to Towers Foundation. “If you come out here and you join us one day, you’re going to join us on our mission. You’re going to see all these great Americans that are willing to do so much for us to protect us.”

Siller started the organization in honor of his brother, and always remembers his heroism.

“He got a call on his radio scanner that the towers were hit. He got a call to duty, went back to his firehouse and got his gear. Just what first responders and our military do all the time, right? They respond. They run towards the danger and get us to run the other way,” Siller said.

The organization has raised more than $250 million and provided more than 450 homes.