Runners tackled more than 2,200 steps of One World Trade Center — and it's all for a good cause.

It's part of the second annual Stephen Siller Tunnels to Towers Tower Climb.

The climb took six waves of 1,000 participants to the 102nd floor, just two shy of the building's top floor.

The first wave of runners was made up entirely of first responders from the NYPD, FDNY and Port Authority.

"It's no small task climbing 102 stories by any means, but to do it with the emotion that most people have that are going up these staircase, to think about 9/11, the north tower the south tower, what this building represents now, which is both those buildings, the loss of life and the heroism on that day," said Frank Siller, chairman and CEO of the Stephen Siller Tunnels to Towers Foundation.

Proceeds from the event will help fund high tech smart homes for wounded military veterans.

The climb is named in honor of the firefighter who ran from his car on the Brooklyn side of the Battery Tunnel to the World Trade Center towers during the September 11 terror attacks.

He was killed when the towers fell.

Family members of fallen police and fire employees served as the climb's honorary starters, including the widows of slain NYPD  Detectives Wenjian Liu and Rafael Ramos.