In December I traveled to the Cajon del Estero Aucayes, using horse support to reach a base camp at ca 2,500m. The next day I left for a group of mountains that run from north to south and close this valley from the east. Cinco Mil (3,658m) lies along this chain. From base camp it took five hours to reach the base of the mountain. I ascended the southwest face on slopes never steeper than 40° to a final section of steeper rock. The ascent was not technical—the focus of the climb was to explore an area very little visited by mountaineers. This area has high potential for first and second ascents and new routes.