The marines' mountain warfare training center is the ultimate test for some of the world's toughest troops: a make-it-or-leave regimen of backcountry ski combat, torturous night maneuvers, and deadly cold. Any volunteers?
So, feeling like a plunge down a Himalayan river, a race up the face of a Patagonian spire, or a ski expedition to the North (or South—that's O.K. too) Pole? Feeling a little scared? That's why we call them Tough Trips.