Monte Pissis is the third highest mountain in South America, behind Aconcagua (22,841 ft.) and Ojos del Salada (22,572 ft.). Monte Pissis is an extremely remote mountain, rising east of the Argentina-Chile border, on the rim of the Altacama Desert. It is seldom climbed because of the length and logistical difficulties of an approach, particularly difficult given the aridity of this desert region. A winter ascent is recommended because snow may be the only source of water.