Transcript for Urban Explorers: Taking Roads Untraveled
This -- of a no trespassing sign makes you turn the other direction -- probably like most people wary of venturing where you're not welcome. The first on the thrill of being where they're not allowed -- where others might be afraid to travel sparks a rush worth risking at all. Here's ABC's -- -- -- Don't worry he's not about to -- Moses gave us just wants to pose for a picture -- here. On the Eagles of the 61 floor of New York's famed Chrysler Building. Such an iconic place everybody has -- of the Chrysler Building Will Smith was hanging out on on the men in black three you do need to break -- Laser alignment is not only can leave the circuit it's an amazing experience and one that you know everybody should be able to have. That experience. Is well known -- urban explorers like gates for them every skyscraper. -- And scaffold is a space just begging to be -- This is like the cat Combs of Paris -- 200 mile made this -- little -- holds the remains of six million. And other underground hideouts and it can even apparently be a great place to party. These guys are not afraid to show off their adventures even though -- technically a group of professional trespass there's -- on -- -- he invited me to join him to try my hand -- practicing what he preaches. My first urban exploration. There are still seeing played instantly when you see. A sewer scaffolding structure. Is in just -- expedition waiting to happen. I don't even really considered an adventure anymore just kind of -- off the beaten path traveler like. Really just a vacation. Week climbing to a -- were walking along the ledge and head out into New York City. To find out what -- his drive to -- urban jungle. I cannot with any eloquence describe why going into a hole in the ground and seeing what's there is cool but I think people understand did almost instinctively I would say. We -- careful not to break any laws for this adventure but now on foot getting -- first destination is tricky. Since when you allow locked gates of stuff you really but we eventually arrive at the high breached the oldest span connecting Manhattan to the Bronx. Keep out. A fence prevents me from going across it. It looks like a great -- action -- really it really is how did you -- interested in this urban exploration. I started just by walking around in. Walking the streets and seeing but I could see how awesome if you talk to really anybody who's just in Urbana files are you Urbana -- and -- -- violent -- they might not identify themselves as an urban explorer but inevitably they have the story about. There isn't this manhole that I -- -- This abandoned observation deck sound or something like that before you put this there is the Wall Street and -- -- gets on top. But -- it's not even just personal it's really a larger movement for the greater good right you wanna see. The places that you're able to go to you want everyone to be able to see them. -- being able to take risks in these kind of risks is something that not everybody can do. But yet everybody should be able to CDs places -- it. A second breach we visit is also closed -- and this frustrating harrowing scenes. Walking people on exploring and makes -- hour poking around here is unfortunately unsuccessful. Determined to have one small adventure we head to our last stop and face the big challenge of the day. This is the Borough of Manhattan -- -- get from Manhattan to the mainland in New York State which is the Bronx. Without crossing a bridge are getting our feet -- And so we're -- see see what's up here and then also underneath there we might be able to get over. We can't go any further. Yet again he had the tide is in quite low enough so we can actually go this way if you -- -- -- isn't there weren't enough to get our feet wet. Well you know how beautiful long -- -- are you this is. -- really the only place you can do it. As we cross Moses curiosity gets the best of want to hear it may just be a hollow space behind that panel but for an urban explorer taking a -- is the whole point well. Decision -- table. There's kind of something you around every corner and he should always trying to poke your head around it. Answer me I can now say I walked on water from the Borough of Manhattan to the mainland of New York. For Nightline I'm Lindsey Davis --
This transcript has been automatically generated and may not be 100% accurate.