17 years have passed since Firefighter Stephen Siller heroically ran a path from the Brooklyn-Battery Tunnel to the World Trade Center on September 11th. He died, trying to help others, when the Twin Towers collapsed.

Now, more than 30,000 people symbolically follow in those footsteps every year to honor him.

"He knew it was a dire situation, and how he could save the most lives possible," said Catherine Christman, Stephen Siller's cousin. "I think that's what's important to know about Stephen."

People took the same route Sunday as part of the 17th Annual Stephen Siller Tunnel to Towers 5K. The foundation's chairman & CEO, Frank Siller, said the event was not just for his brother, but it was also a way to honor the many other first responders who made the ultimate sacrifice that day, as well as those who are suffering, or who have died, from 9/11-related illnesses.

"Some stories you know about, and some stories you don't," Siller said. "There are so many acts of heroism. Stephen is symbolic of all of the acts of heroism."

Some who ran made the trip in memory of someone special. Carmela Raguso wore her late husband's bunker gear as she walked. FDNY Lt. Christopher Raguso was an Air Force master sergeant who died on March 15 when the helicopter he was on hit a power line during a routine personnel transfer in Iraq.

"It feels good. I feels like I'm doing something for Chris. Chris is proud of me," Raguso said.

Sunday's event was not just a race for New Yorkers; people we spoke with came from all over the world just to take part and show their support.

"I'm a London firefighter from London, and obviously I think every firefighter from around the world can empathize with what happened on 9/11," participant Ian Devine said. "It hit everyone's heart."

Organizers say, over the years, they've raised millions of dollars to benefit the Tunnel to Towers Foundation and its programs to help first responders and service members.