NEW YORK (CBSNewYork) – A man on a mission to walk every block in New York City has almost completed the challenge.

Matt Green recently spoke with CBS News’ Kenneth Craig about what keeps him going.

“There’s something that just feels good about being outside and walking around,” he said.

Green has been logging upwards of 25 miles a day for nearly seven years.

“I just thought that was such a cool idea of a way to see a place,” he said.

A man on a mission to walk every block in New York City has almost completed the challenge. (CBS News)

He said his obsession started almost a decade ago when he gave up his desk job as a civil engineer and packed his bags for a 3,000 mile walk from coast to coast.

“I basically had a tent with me and I would knock on people’s doors and just ask if I could camp in their yards,” he said.

Not long after that, he started his trek across the Big Apple. Over the past seven years, he’s covered more than 9,000 urban miles, venturing into neighborhoods native New Yorkers may never see.

“If you’re just walking somewhere and open to seeing what’s there and who’s there, it’s always going to be a fascinating experience,” he said.

Green’s experience has been captured in a new documentary – from his interactions with complete strangers, to his moments of peace.

All of his on just $15. He couch-surfs, living off his savings, donations and pet sitting money.

Craig asks whether there are days he questions what he’s doing and why he’s still walking.

“It’s such a fulfilling thing to do, I don’t have that question in a big-picture sense, but there are days when I get up and I just don’t feel like going outside,” he replied.

Green has just a few hundred miles left in his mission.

“It’s just given me nothing to do in my life other than to look around. Only because of that I’ve realized how much I’ve always overlooked in my life before that,” he said.

He says his walk is a long, open-ended journey and he’s compelled to just keep going.