MILLAU - Julien Millot has walked in the sky between the two Atomium spheres in Brussels, above the "Troll's wall," Europe's highest cliff in Norway, and, last July, in the Dourbie ravines near Millau, France for the Natural Games.

"The first time you get up on a high wire, you think you're going to die," Millot explains. "You wonder what you're doing there, and want just one thing: to get off, really. It's your survival instinct that's telling you to stop."

The 30-year-old tightrope walker must have tossed his survival instinct down into one of the chasms that he spends his life crossing. Millot walks across these massive voids on a flexible two-centimeter-wide wire like a normal person would pace the sidewalk. All he has for balance are his arms and a small piece of rope that attaches him to his strap - and to life, if he falls.

"This sport looks dangerous but it really isn't when you do it in good conditions," he says. "The strap is coupled with a climbing rope underneath, and we wear a harness attached to this with another rope and rings. All of this equipment is designed to support two tons."

The high-wire walker's equipment is similar to a climber's because both universes are intrinsically linked. Scott Balcom, an American keen on rockclimbing, stretched the first wire in 1984 in Yosemite, California. It took him a year to pluck up the courage to attempt and succeed a crossing that has since become a Mecca of sorts for these self-anointed "skywalkers."

Cold fear

But being a regular rockclimber doesn't automatically make it easier to cross a high wire, says 29-year-old Tancrède Melet, Julien Millot's inseparable companion. "It's very different from rockclimbing, where there is a direct connection with the void but also a systematic connection to the rock. A lot of climbers are scared shitless before they can stand up on a high wire."

Before you attempt to cross a high wire, it is imperative to first be able to cross a "slackline" that is at least twice as long, on the ground. For the aerial dimension of highlining makes things even more difficult: you have to learn how to start sitting down, how to get back up after falling, and how to deal with emotions that are multiplied tenfold.

"When you start skywalking, there's a first step you have to pass before you can start enjoying it," says Millot. "And that step is extremely brutal. Sometimes people cry because on the ground they felt fine, some of them even do extraordinary things but they feel crushed up in the air." The joys of skywalking are therefore reserved for a small elite: in France, there aren't more than 40 autonomous walkers who can painstakingly set up and cross a line.

Twenty-six year-old Mathieu Mouroux is one of them. Despite his four years of experience and his trust in the equipment he uses, he hasn't completely kept his fears at bay. "When you fall for the first time, when you know you're going to screw up, all of a sudden, you wonder if the small security rope is going to hold. Well, it always holds, but the pressure spike is phenomenal." Some dive into the void on purpose at the beginning of a session. "It hits you head-on, but it's reassuring. If the installation holds up, you can go on more calmly."

A real high

This is how Julien Millot describes the pleasures of a wire walk across a void. "It's a solitary pleasure. You're surrounded by emptiness and silence. You concentrate on your feelings, on your thoughts. On long lines, over 40 meters, you spend almost five minutes walking over the void, and on some portions of the strap you experience a sort of ecstasy. But it all depends on the people, because the line amplifies emotions. If you feel good, it'll be great; you can let your spirit empty and enter a trance. If you're afraid, the line will reflect that, and the fear you feel can become monstrous."

As though all of this wasn't breathtaking enough, a few extremists push it so far as to do "free solo," the mere mention of which ties the stomach in knots, because the goal is to cross the highline with no security other than your own sense of balance. "The first steps aren't the nicest," says Millot. "You trust yourself and your technique, but you can't help thinking: ‘What if something went wrong? What if my heart skips a beat, even a single one? What if I get a mosquito on my face? Am I making a huge mistake?" But you quickly get back into your state of concentration and serenity, and you know you are going to make it to the end. That being said, you don't have fun trying out new things, and you don't go at it with all you have. I've done an 85 meter highline, but I won't free solo that."

Seen from below, free solo rather spells certain death for those who fall. "It's almost a metaphysical approach," suggests Tancrède Melet. "I'm not suicidal, but getting so close to death, playing with life and death, it indicates a certain curiosity about the universal and extemporal questions of ‘What is existence?" Maybe we're looking for the answer to that question."