They've faced claustrophobic spaces and some mentally exhausting challenges thus far, but the hardest challenge to date could arrive for one team on The Amazing Race.

Sheri and Cole have mostly kept near the back of the pack so far, and their ability to last in the long run could be tested when teams head to the French Alps in Chamonix and face some tough challenges while 15,000 feet in the air.

Among the challenges they'll face is climbing across a tightrope across a mountain top in order to obtain a next clue—and with Sheri's panic over being so high up, it could hurt her and Cole as they try to pull towards the front of the pack.

"I'm so scared," she cries in a preview clip for the Friday, March 11 episode.

However, they won't be the only ones who could face potential trouble along the leg, as teams also face challenges with dynamite and possibly hang-gliding through the mountains. And the possible danger could frighten some of the other competitors as well.

However, at least one team will be psyched by the tasks: Brody and Kurt.

"We're only doing freaky stuff today!" Brody says with excitement in the clip.

His excitement is noticeable throughout the clip, as he and Kurt appear to dominate their way through all the challenges, with each one only seeming to excite Brody more and more.

"This is sick!!" He shouts.

The Amazing Race airs Fridays at 8 p.m. on CBS.

Tags: The Amazing Race CBS Reality TV