A Colorado man set out to run 85 miles Friday in honor of the first responders who died on September 11, 2001.

“You know, I'm certainly not alone in being profoundly changed by the events of that day,” 44-year-old David Clark said. “I grew up in New York. And I just remember walking through those streets and those areas. And seeing everything that was transpiring on that day was just devastating.”

The Lafayette resident said he wanted to run 343 laps in honor and remembrance of the 343 firefighters who died after they ran into the burning World Trade Center Towers to save others 14 years ago.

"We hear about it all the time," Clark said, "the bravery and everything that happened that day. But really stopping and thinking about what it must have been like for those guys… they must have been scared. But they overcame that and went in there selflessly."

"That's amazing and that kind of human spirit speaks to me," he said. "And I just wanted to honor them and what they stand for. And not just them, but all the firefighters that do that every day."

Clark started running just after 7 a.m. He hoped to run his final lap by 10 p.m.