Tens of thousands of runners pounded the pavement Sunday in the annual Tunnel To Towers run to honor a hero firefighter and others who lost their lives in the September 11 terror attacks.

Runners stepped off for the 5k run around 9:30 a.m. in Brooklyn to honor first responders and civilians who lost their lives on September 11.

Participants followed the footsteps of firefighter Stephen Siller, who sprinted through the Brooklyn Battery Tunnel to the World Trade Center that day while carrying 60 pounds of firefighter gear. Siller died when the south tower collapsed.

The money that is raised goes to a number of local initiatives for first responders and military personnel.

NY1 spoke with a firefighter from London who says he has ran in the race since 2004.

NY1: Why do you come back here year after year?

London firefighter: Just to honor what Stephen did and what all the first responders did that day, such heroes in my eyes, and also being a London firefighter, it shows a little bond between us and the FDNY and what happened.

People have participated in the run since 2002, evolving from a few thousand runners to, this year, around 30,000.

For more information on the Stephen Siller Tunnel To Towers Foundation, head to www.tunnel2towers.org