From our base camp on the glimmering shores of Sirki Khota Lake, Robert Rauch, Stefan Berger, and I spotted a logical line on the southwest face of 5,546m Serkhe Khollu, which is the main summit of the Serranias Serkhe and Murillo, situated between Mururata and Chacaltaya. On June 10, in total darkness and sub-zero temperatures, we searched for access to its base. Not even three meters wide, the icefall soared vertically upward. We sorted our gear, racked up, and stepped into unknown terrain. On the second pitch, the ice surprised us with poor quality, and every swing of our picks at that altitude felt like hard work. On the fourth pitch, the ice tube unexpectedly ended, forcing us onto sparsely protected mixed terrain with brittle ice. Happiness lit-up our faces as we reached the next ice tube, and we climbed faster—a good thing, as the sun illuminated seracs overhead. But we managed to escape the danger zone. Pitches of 75-85° glacier ice followed, and we climbed quickly. In the last two pitches leading to the summit ridge, the glacier steepened again but Stefan led us through with confidence, and we crested the ridge after ten hours of climbing 600m of ice and mixed terrain.

The descent, not technically challenging but littered with crevasses, led down to a scree field that again called for surefootedness and concentration. We donned our head torches and continued back to base camp. So near the equator, the transition from day to night happens without twilight. Our new route, Chamaka (Aymara for darkness), began and ended in moonless darkness.