By NEAL KARLINSKY, BRANDON BAUR and LAUREN EFFRON

The mountain is Mexico's El Sendero Luminoso, "The Shining Path." That guy in the red shirt climbing the rock wall, without a rope, safety equipment or even a helmet, is Alex Honnold.

During his solo climb in January, the 28-year-old extreme free climber made it 2,500 feet up to the summit of El Sendero Luminoso in little over three hours, his life suspended by just a few toes and fingertips, and incredible concentration.

"Generally, when you're soloing you're just so focused on what you're doing or you're just sort of empty and you're just executing what you have to do," Honnold said.

Extreme free climber Alex Honnold free-soloed El Sendero Luminoso (The Shining Path) in El Portrero Chico, Mexico. Credit: Camp4

Tracing Honnold's climb. Credit: Camp4

Honnold is easily regarded as perhaps the world's best mountain climber. He holds a number of speed records for climbing sheer faces in Yosemite without ropes. But surprisingly, Honnold is pretty mellow, especially for a guy who has to constantly talk about fear, danger and death - all topics he would rather avoid.

"All the soloing I do without a rope, it looks crazy, like, 'oh wow, you're on the edge of a cliff. But seeing a photo like that doesn't give any indication of how likely I am to fall off," he said. "It just shows that if I did fall off it would be a disaster."

"Truckers do the same thing. I mean, if they lose concentration for a few seconds and veer off the highway 80 miles an hour, they will die, but do people consider [truck driving] extremely risky? No, because the risk is quite small," Honnold said. "I see all of life as an odds game, you know, everything you do has risk… so I choose my risks carefully."

Honnold's good friend Cedar Wright is an accomplished professional climber in his own right, but even he said he occasionally gets concerned about Honnold.

"I would be lying if I said I didn't worry about him," Wright said. "He's an extremely accomplished athlete and calculated and I would say empirical in what he does. But at the same time, there are things he can't account for, like a rock could break or a bird flies out of a crack or something. He's playing in a game where the ultimate stake is to lose your life."

Honnold insists he gets too much attention for what's called "free soloing," going without ropes, arguing that 90 percent of his climbs are with ropes. But it's hard to argue the "one slip and it's over" impression around someone who is clinging, ropeless, to the side of a mountain.

"There have been tons of things I've gone to solo and then decided not to," or times when he began a climb and decided "'I'm not feeling it,' and gone home," Honnold said.

Alex Honnold facing El Sendero Luminoso. Credit: Camp4

Even he has had his moments, frozen on a mountain, fear fighting for a toehold alongside him.

"It's one of those things where you stand there for a minute feeling sorry for yourself and it's like, 'well, I better pull it together,'… and then I finish climbing," he said. "The thing about soloing, or climbing without a rope, is it's a very rewarding experience, very satisfying. There's a reason I like to do it because I get a lot from it. But at the same time, it's not something I can do all the time."

Being a professional mountain climber means being a bit of a nomad. Honnold's sponsors pay him to climb the world's most beautiful mountains year-round. He has even popped up in the occasional TV commercial. Honnold is originally from the Sacramento area, but when he is in the U.S., he lives and travels out of his van. His life is, all at once, extreme and extremely simple. He makes a good living, but spends virtually nothing on himself.

During the "Nightline" interview, Honnold and Wright were in the midst of a grueling 700-mile bike and climbing trip they called "Sufferfest 2? in the U.S.'s Four Corners region, across Colorado, Utah, New Mexico, and Arizona - a new challenge for them after last year's "Sufferfest" in California. Wright made a 17-minute film called "The Sufferfest" about their first tour, and is now working on the sequel.

This year's trip included stops for Honnold's charity foundation, which provides solar panels to Native American homes without electricity.

"I used to be quite scared of speaking in public and things like that, but I've gotten over it because of this," he said.

It's about as far from a 9 to 5 lifestyle as you can get, and Alex Honnold, conqueror of mountains, has no intention of slowing down.

"What's cool about climbing is you can go out in the mountains your whole life and just enjoy," he said. "I think that most climbers live to old age. I'm hoping to retire with grandkids and stuff."