Trail of los Pantanos Activity · Velilla del Río Carrión, Montaña Palentina, Palencia Image of Velilla del Río Carrión, not of the place itself. The Ruta de los Pantanos (Route of the Reservoirs), also called the Ruta de las Aguas Mansas, runs through the Montaña Palentina, in northern Palencia, linking Velilla del Río Carrión and Cervera de Pisuerga over 55 kilometres along the P-210 road. The route starts in Velilla and skirts the Compuerto reservoir, whose dam was completed in 1960 next to Otero de Guardo, and the Camporredondo reservoir, one of the oldest in the province, inaugurated by Alfonso XIII in 1930, before passing Cardaño de Arriba, Alba de los Cardaños, Triollo and Vidrieros. Towards Cervera it also crosses the Requejada and Ruesga reservoirs, on the Pisuerga side, among peaks such as Peña Prieta, Espigüete and Curavacas and forests of beech, pine and oak. Photo: Goldorak (CC BY-SA 3.0) What to see and do in Velilla del Río Carrión