On March 19, after a small incident in which we had to extract the car from some mud, my wife dropped me at dawn at the “road head” (ca 4,800m) a little short of Serkhe Lake. I then climbed the southwest face of what some call Serkhe Negro (5,460m, 16°23'14.70"S, 67°57'1.83"W). Descending the far side, I broke a crampon as I downclimbed in a narrow gully and hit rock under the snow. Once I'd fixed it with some cordelette, I continued onward to climb Serkhe Khollu (5,546m) via the northwest ridge, which was an easy undertaking. The descent, slanting down and across the southwest face, was a different matter: difficult, steep, and scary. I used my 35m rope to rappel short vertical sections.
Once back on the valley floor, I had a little break before continuing to Peak 5,540m (16°24'40.09"S, 67°56'51.80"W), which is sometimes referred to as Khasiri or Qasiri, though this is also a name given to a peak farther south. I chose a steep, snow-filled gully on the north face and followed it to the summit, arriving in midafternoon. Once again, the descent—along the northeast ridge—was more difficult, and I rappelled several short sections. I bivouacked beside the shore of Serkhe Lake and left the next morning. As is often the case in Bolivia, this adventure was wild, beautiful, and astonishingly close to civilization.
– Alexander von Ungern, Andean Ascents, Bolivia