Transcript for Young 'High-Liners' Defy Death in Exotic Locations
Reporter: They are the hi highlining daredevils whose ultimate rush is conquering slack lines in picturesque countries. Their latest feat -- a lot of people keep telling me come to brazil. And so I finally was like, okay, we're going to brazil. Reporter: Andrew lewis, brian mossbecause. Haley ashburn and scott rogers are the adrenaline junkies who just dominated the longest slack LINE IN rio de Janeiro, brazil, 3,000 feet above ground. Their life hanging in one waist-tied harness. You're just about having fun. All of it, the reason we do it, it's just fun to us. Reporter: Pictures capture them balancing their bodies, sitting cross-legged, even dangling upside down. Scariest moment, probably hanging by my ankle would be the scariest moment for me, I would say. We got a first taste of andy's fearless slack lining skill at last year's super bowl when he wowed the crowd at madonna's halftime performance. But traveling the world and discovering new high lines is fulfilling a lifelong dream. Crazy from the outside and maybe it is crazy to follow your dreams. For us high lining up there in the clouds all the way above rio. Reporter: It takes years of training and dedication to get there. Like trial and error, basically, learning how to do it safely. Was a trial and error and the errors haven't been so drastic. Reporter: The key to the stunts that pushed them to the max is fearlessness. You're fearing for your life you're out of your depth. I don't think we would do it if we thought we would die every time we would do it, it would be a terrifying experience. The leader of the group says high line something safe when you do it with a leash. Without a leash it's called free soloing, the consequences of a slip there almost certain death so wear your leashes. Without a leash it's called done. Thank you. John, we thank you and coming up, jacoby jones, boy,
This transcript has been automatically generated and may not be 100% accurate.