Yet for one of the climbers, a World Trade Center site worker now fighting cancer, returning to Ground Zero was especially meaningful.
"It's just so unexpected," said retired New York Police officer Ron Pechtol.
Pechtol, who has been with the NYPD for more than 15 years, has an emotional journey few could imagine. As a 9/11 responder, he calls the terror of that day his worst day.
LINK: VIEW PHOTOS FROM THE RUN
"The air was not blue anymore it was brown," he recalled. "All kinds of whatever was in the air."
But that was not the last daunting day he would face. During an annual post-9/11 health exam for responders, Pechtol was diagnosed with Multiple Myeloma.
"That dire diagnosis came two days before my 25th wedding anniversary," he said.
After 15 years on the job and retirement ahead, it was crushing to hear he had blood cancer.
"You don't realize on outside looking in but when you do have it your whole world changes," he said.
With a resolve to return to the site that changed his life, he signed up and trained for the charity climb ? an event designed to fight cancer one step at a time.
"That's the most important thing," said Pechtol. "Eradicating this disease and having a fun way to do it. Like this climb."
On the 72nd floor, he joined 700 climbers ? including Eyewitness News' own Amy Freeze's team ? and proceeded to celebrate at the top with a guest interview by Giants Punter Steve Weatherford.
"I finished!" he exclaimed.
Returning to Ground Zero marked the end of a chapter in Pechtol's struggle. Much like he did as a 9/11 responder 13 years ago, he has made a difference again, this time joining New Yorkers in the fight against cancer.
Together, they raised almost $200,000 ? every cent for cancer research.