The Puerto de las Signales, in the north of the province of Leon, is one of the highest in the Cantabrian mountain range, a setting of exceptional beauty that guards surprising natural treasures. One of them is the Pinar de Lillo which, with an estimated age of 4,000 years, is classified among the most important in the Iberian Peninsula due to its magnificent state of conservation, its high ecological value and the great variety of flora, fungi and fauna.

In the heart of this forest the Porma River rises, thus beginning a path towards the south in search of the other great Leonese river, the Esla, to which it gives its waters.

In its course it creates magical corners in which wildlife harmonizes with human activity in a sustainable way, structuring the western end of the Montaña de Riaño and Mampodre Regional Park.