Parque Provincial Aconcagua

South America's tallest mountain is Aconcagua, located in the Andes in western Argentina near the Chilean border, towers at 22,841 feet. It takes about two weeks of trekking to reach the summit and you'll need go with a guide. Try booking with Discover the Andes, a local tour outfitter that provides bilingual guides. The main route, which follows the northwest ridge of the mountain, is not technical, but because of the extreme height the altitude can pose a problem to climbers.