By BEN NEWMAN and LAUREN EFFRON

When Sasha DiGuilian isn't in class at Columbia University in New York City, she can be found taking on an unimaginably sheer ascent in some foreign country.

"I'm afraid of sharks… I have small fears, but I don't like feeling not in control, and with climbing, I feel in control and maybe that's why I feel more fearless," DiGuilian told "Nightline."

Sasha DiGuilian, 21, is already a world champion competitive climber. Credit: Christian Pondella/Red Bull Content Pool

At just 21 years old, the Virginia native is already a world champion competitive climber. She lives for climbing rock walls so steep, so remote, so seemingly impossible that they rattle would anyone who attempts them.

Recently, DiGuilian allowed "Nightline" to tag along as she tackled an extreme climb on Sardinia, an Italian island known for its rugged coast and brutal climate, to become the first woman to successfully ascent the 1,000-foot climb there.

"This is by far the hardest route that I've ever attempted," she said. "It's about 1,000 vertical feet… one of the world's most difficult multi-pitch climbs."

Credit: Christian Pondella/Red Bull Content Pool

Credit: Christian Pondella/Red Bull Content Pool

So difficult, that it's only been fully climbed once before. Legendary climber Dani Andrada of Spain and his climbing partner Daniel DuLac of France established the route, known as "Viaje de Los Locos," or Mad Man's Journey, in 2002 and since then no one has successfully completed the route.

"It's been 12 years since this route has seen another ascent and that's what we're going to try and do," DiGuilian said. "I'll try and be the first woman to do this climb."

DiGuilian originally had her sights set on a 1,000-foot climb in the Swiss Alps. She planned and trained to take on a cliff called Zahir Plus, a jagged route few climbers have completed. She was joined by a documentary team from Red Bull , one of her sponsors, who had hoped to film her attempt on Zahir Plus, but when the team got there, they faced persistent torrential rains and had to abandon the site.

So DiGuilian and the team took a huge risk and set out for Sardinia instead. "Viaje de los Locos" is broken up into seven sections called pitches.

"Arriving to the wall it all of the sudden hit me, 'what are we getting ourselves into?'" Diguilian said. "I definitely felt like I was exposing myself to the hardest thing that I've tried yet in my climbing career which was a really cool feeling but also … almost nauseating."

Fellow professional rock climber Edu Marin of Spain joined DiGuilian for the climb and the two spent days exploring the wall, some of which had been reclaimed by nature, and plotting their ascent, one move at a time.

"Climbing a long, hard route is almost like taking a music composition and breaking it down into its single form and kind of learning the piece," DiGuilian said. "You're breaking it down from being able to memorize and master one section to eventually being able to master the piece in its entirety."

Sasha DiGuilian and her climbing partner Edu Marin of Spain prepare to climb "Viaje de los Locos" in Sardinia, Italy. Credit: Christian Pondella/Red Bull Content Pool

In total, the team spent nine days preparing for the ascent, going over their climbing plan and DiGuilian's biggest fear - falling from one of the pitches, which could end the whole climb, or worse, cause horrific injury, even death.

"You'll cheese-grate down the barnacle-ly painful surface of the wall [with] increasing velocity," she said, accessing the wall.

Sasha DiGuilian during her ascent on the 1,000-vertical cliff, "Viaje de los Locos," in Sardinia, Italy. Credit: Christian Pondella/Red Bull Content Pool

Risks on these climbs are calculated, DiGuilian said, and she never climbs without ropes, known in the climbing work as a "free solo" climb. Moving the climb to Italy ended up having a powerful, personal meaning for DiGuilian because two months prior, she lost her father, who was Italian.

"I know how much of an impact that would be on my loved ones if I were to pass," she said. "Seeing other people in my family being affected so strongly by my dad's death, myself included, obviously, it really makes you feel like life is really sacred."

Watch what happened when Sasha DiGuilian takes on the full climb tonight on "Nightline" tonight at 12:35 a.m. ET, and watch Red Bull's documentary about DiGuilian's climb HERE.

Sasha DiGuilian says she always uses ropes when she climbs. Credit: Christian Pondella/Red Bull Content Pool