Height: 22,902 feet
Challenges: Elevation, Snow Traverse, Access
Relative Difficulty: Moderate-Difficult
This massive Andean mountain is South America's member of the famed “Seven Summits.” Records show that about 60% of climbers who attempt the summit succeed, and that most failures are caused by altitude sickness and hypothermia. While this adventure is no joke, familiarity with crampons, ice axe self-arrest, trek camping and moderate alpine climbing experience are all you need to call this intimidating feat—which takes about 21 days, including the trek in and acclimatization—non-technical hiking.