Last Summer, Mich Kemeter walked 820 feet (a distance greater than two football fields) across Austria's Green Lake on a one-inch-wide strand of synthetic fiber in 19 minutes – setting a new world record for slacklining. A sport similar to tightrope walking, slacklining requires athletes to traverse a flat strap that has the stretchy bounce and give of a trampoline (think of a tie-down for a car's roof). Over a period of 20 days, Kemeter tried to complete the crossing 35 times while teetering 18 feet above the frigid, 44-degree water – a gust of wind could have sent him toppling over.

"I didn't think slack­lining would become such a big part of my life," says Kemeter, a 25-year-old climber and BASE jumper. "I was just looking for something new to try."

In 2011, the Austrian daredevil made headlines for slacklining 3,000 feet in the air with no safety harness between two peaks in Yosemite Valley. But the more tranquil Green Lake crossing carried personal meaning – his conservationist grandfather saved the lake from developers a few years ago. "He fought for more than a decade," Kemeter says. "This was a big motivation for me." Despite his initial failed attempts, Kemeter maintained a Zen-like philosophy throughout. "Slacklining is cool because you can compare it to life," Kemeter says. "It doesn't matter if you fall during the last few feet – it's all about taking the next step."