The only thing I’ve ever balanced on was a low-to-the-ground beam in gymnastics or short stretches of curb that threatened to roll my ankle had my dad let go. So let’s just say balancing isn’t exactly my forte. But for some people it’s not only a skill — it can even help pay the bills.

When he’s not doing improv, sketch comedy, or making films, trusts his safety to a two-inch wide, flat-but-flimsy rope. Greenwood is a sponsored Slackline athlete who practices a balancing act way more impressive than just walking one foot in front of the other with outstretched arms.

Slacklining is not a lazy form of line dancing. The name spawns from the flat, bouyant line that's a lot like a super skinny trampoline. The daredevil sport involves balancing along (and hurling one’s body against) this narrow, flexible piece of webbing which is fairly low to the ground and anchored to two standing points (often trees). And though Slacklining is nothing short of strenuous, terrifying, and unconventional — its athletes are called “slackers.”

It may look like an act pulled straight from the circus, but Slacklining is the real deal (and not just for a bunch of hippies): There's a detailed rule book, championships, and a . It’s all about letting go, and trusting a very, very small surface area to bear your bodyweight.

The can be traced back to the mid seventies at climbing camps in Yosemite National Park. When blazing new routes, climbers would rig ropes to walk from one point to another. Turns out, balancing on a climbing rope improved core strength and balance. Now Slacklining has evolved into a popular (and super cool) cross-training sport for the sake of fun and fitness.

Oh, and we cannot fail to mention: This clip’s star taught Madonna how to slackline for her world tour (!).

Would you ever try slacklining? Have you? Let us know in the comment section below or tweet the author .