A mule train walks through the Ahmegino Valley on its way to Plaza Argentina, one of two main base camps on Aconcagua. Reaching the base camp from the nearest road involves a three day hike over more than 25 miles of arid terrain. The peak is the highest summit in the western hemisphere and the highest mountain outside of the Himalaya at nearly 23, 000 feet tall. Despite an absence of technical difficulties, only about 40 of climbers reach the summit. Many others succumb to the extreme weather, dry air, food sickness or other medical concerns that arise at the high altitude.