Cambridge Andean 1957
Having tried to access their objective, Pumasillo (5991m) from the north, only to find this route impassable, this party eventually found a viable approach route from the south. After establishing basecamp in the basin at the foot of the mountain's west risdge, they set about passing first an icefall and then an ice buttress in order to access the west ridge proper which they considered to be the mountain's only viable route "with current techniques". Passing the icefall was complex but relatively easy, while the ice buttress proved to be a more taxing affair with the need for significant points of aid. Easdier climbing followed to within 500 feet of the summit, where they were forced onto the south face, overcame a steep ice pitch and eventually navigated the complex summit ridge to reach the summit itself. Over the course of six days, the whole party reached the summit, Gravina and Clark being the first party to do so on 23 June. The expedition also climbed three additional 5000m peaks during their time in the region.