RED HOOK - Thousands of runners and walkers retraced the footsteps of a fallen Brooklyn firefighter during the 9th Annual Tunnel to Towers 5K today.

The event remembers Stephen Siller, who died after running through the Battery Tunnel from his Brooklyn firehouse to reach the World Trade Center on Sept. 11.

This year, the race drew 20,000 participants, including school groups, sports teams and members of the military. In Afghanistan, service members also participated in their own run to honor his heroic action.

Siller left behind a wife, five children and six siblings. The race benefits the Stephen Siller Foundation, which has given millions to various children's organizations across the city.