Maria Lloco and Huayna Potosí, Cordillera Real. On July 31 Karl Collins, Ross Macfarlane and I climbed Maria Lloco (5639 meters, 18,500 feet) by its east ridge. On August 3 Macfarlane and I completed the ascent of the west ridge of Huayna Potosí (6096 meters, 19,996 feet). This climb was the hardest of the expedition. (We were also in the Pumasillo group in Peru.) It demanded two full days of continuous ridge climbing with numerous pitches of technical rock and ice. We bivouacked twice and descended the southeast face.