PR-S75 Riberas del Yera y Ajan goes through the square of Vega de Pas and some neighbourhoods of Yera river and Aján river.

The ancient communication trails between plots and cottages allow us to walk a comfortable path, that offers us the opportunity to see the ecological and landscape values of the ENP LIC Río Pas.

Among those values, are specially notable the alder and oak forests, or the presence of emblematic species of our rivers like the Iberian desman or the local crab. Are also present some protected amphibious.

Among the most significative birds, we point out some birds of prey, and other small species that can easily be seen on the riversides and forests.

Walking along the left side of the river of Yera, crossing the cottage neighbourhood, This is the meeting point between Yera and Aján, where we go into the reducted and spectacular headwaters of Aján through Cañao de Aján.

The old stone path a basic element of cottage neighbourhoods, is accompanied by willow trees (Salix spp) or ash trees (Fraxinus excelsior), and later by hazelnut (Corylus avellana), beech (Fagus sylvatica) and oak (Quercus robur) trees.

After a comfortable ascend, we reach El Mingán, the end point of the route. Here we can see the remainders of old buildings used by the workers in the construction of the railway Santander-Mediterráneo,  a historical symbol of the region’s isolation.

The original goal of that railway project was to link the regions of Santander, Burgos, Soria and Zaragoza with Sagunto and Valencia. The project was included into the “Plan de Ferrocarriles estratégicos y secundarios” in 1908. Once approved, the project could not go ahead. At first this was due to the construction businesses not trusting its results, later the First World War and finally because, after the war when a good part of the construction was already underway or finished , political interest moved from communication to military reasons. The new Government project, that involved the Spanish width railway, did not include Santander.

The tunnel of Engaña, the most important work of the route and the remains of the station, remind us of a frustrating history. The project abandonment was the ending point for the Pas region, since its isolation was met with the economic change from the agrarian sector to others.

We later cross three tunnels before reaching Yera. From here, we descend through different trails that will take us to the Yera riverside and Vega de Pas, while discovering ethnographic and tradition values of the Pas Valleys.

Yera valley has one of the biggest cottage neighbourhoods in the region, mostly composed by “vividoras”. We can even find some linked cottages, sharing their walls. The most striking example is that of four linked cottages, called Corcus.

There are in Yera also small, circular gardens in some plots. The loss of homogeneity thanks to interventions on buildings and their setting is the most notable aspect of these cottage neighbourhoods.