No activity combines characteristics of the Adrenalist lifestyle more than slacklining (sometimes referred to as highlining). Balance, bravado and bullheadedness are needed in equal measures. First, there’s the not-so-simple task of climbing a mountain. Then, there’s actually rigging a line spanning two summits, which can sometimes mean two different climbs. After that it’s just a run-of-the-mill walk across a thin, droopy line swaying in the wind with only a rope or a parachute to save you from plummeting to your death. That’s why slacklining is on the fringe of the fringe: the periphery of an already small group that’s far from anything resembling mainstream. As one slackliner describes it: “most people think we’re crazy,” which sounds like. our kind of people.

Slacklining is similar to tightrope walking except for the dynamic way the rope moves. That’s because slacklining, as its name suggests, provides slack in the line. Rather than the taut line of a tightrope walker, which remains static throughout the walk, a slack line is kinetic with an extra amount of line added making it sway up and down, left and right. Like a much-leaner hammock, a slackline is a nightmare for vertigo sufferers, and a jostling, dangerous trip for those undaunted individuals that traverse the line from hundreds, sometimes thousands, of feet in the air.

There’s not much touching the soles of the slackliner’s feet as they dance across the tiny, one-inch wide, nylon surface of the typical slackline. A slackline walker’s purview is juxtaposed between the stationary ground and the parabolic swing of the line. This confuses the senses and generally knocks people off balance.

Dean Potter, one of the originators of slacklining, walked across Yosemite Falls on a slackline early in August of this year. The cascading falls below him added an element of motion that tricks the senses even more. There is the movement of the line, the trajectory of the falls, and the stationary ground. Equilibrium is almost impossible. In the video, Dean uses a safety rope and does a leg-sweep to catch him when he falls. The rope gives him a backup if he loses his balance and can’t sweep his leg: an important last resort before death.

Sometimes, rather than use the rope attachment that slides along behind the slackliner to secure the walker to the line (the preferred safety measure for all the top slacklining videos you see), slackliners will use a small parachute. This is a rather precarious safety measure because if you fall off the line, you have to be far enough away from the cliffs and line you don’t entangle your parachute. Or, like a man addicted to epinephrine, you can purposely jump from the slackline to combine B.A.S.E. jumping with slacklining and create BASElining.

BASElining is also popular with the current world record holder for longest solo slackline completed (103.5 Meters, 105 ft high in Moab, UT). For Andy and Dean, BASElining is a thrill; for the rest of us, it’s playing Russian roulette with two bullets.

Another slackliner, Christian Schou holds the **unofficial record for the highest slackline at 1000 meters up in Kejerag, Norway, but most slackliners practice at lower levels. They even make up tricks and routines for competition on the lower lines where death is NOT tapping you on the shoulder.

But that’s not really in the spirit of the Adrenalist. The fear of slacklining is often just as strong as the joy of completion when you’re on an insecure line that could extinguish your corporeal self. To attain true enlightenment, Dean Potter will slackline without a net, without a rope trailing behind, and without a parachute. If Dean falls off the herky-jerky line, he dies. Mr. Potter claims the omnipresence of death on a slackline lends him an air of transcendental calm like that of a monk in a monastery. It better, or he’ll drop right off this mortal coil.

**Aleksander Mork has also gone above 1000 meters.