The basins of the rivers Pas, Pisueña (Carriedo) and Miera are always green and perfectly fit the most spread stereotype regarding Cantabria: intricate valleys, pastures that fade away behind the hillocks in the mountains and people of reserved nature. These three contiguous valleys, until recently not interconnected by road—nowadays, driving around is not a problem, except when there are heavy snowfalls in winter—have long been connected via mountain passes of the same mountains that divide them, due to the transhumance practiced by their people, the “pasiegos”. The most important villages are Liérganes—whose older part has been listed as a historic-artistic ensemble, Villacarriedo and Selaya.

The spas of Puente Viesgo and Liérganes, with their respective hotels, are recommended places that can be a starting point to get to know this part of Cantabria.

These lands have been populated for centuries, and this is reflected in the landscape. Huts are dispersed all over the steep pastures. The “Tres Villas Pasiegas”: San Pedro del Romeral, Vega de Pas and San Roque de Riomiera are the best example of a way of life that their people have passed on from generation to generation. The well-cared for meadows, even though they have been created by men over the centuries, constitute another attribute of an ecosystem in which nature and traditional ways of life blend perfectly. The valley of Miera, with ravines that have been carved into the rock by the river, is the most enclosed valley of the region, and at the headwaters of the river there is a cirque glacier. The native forest—hazelnut trees, ash trees, chestnut trees, oaks—has been rather reduced in favour of pastures

Historical and artistic heritage is scattered around the area. The architectonic ensembles of Vega de Pas and Esles are notable because they show the typical features of the folk houses. The palace of Soñanes, in Villacarriedo, is also worth a visit.

The caves of Puente Viesgo are noteworthy for their rock paintings that date back up to 30,000 years.