Castroviejo is a rocky spot in the Sierra de Urbión, in the municipality of Duruelo de la Sierra, modeled by erosion on conglomerates that have been left in whimsical shapes, natural walkways and small hollows between high mountain pine forests. The whole is reminiscent of a small enchanted city, with isolated blocks, cracks and rock terraces that create a very recognizable landscape in the Soria mountains. From the point of visit you can walk through meadows and rocky outcrops with wide views over the sea of pines and, on clear days, over the relief of the mountains. The environment allows to link with the Route of the Waterfalls and with the area of Cueva Serena, where the water appears in the form of waterfall and curtain at the foot of a cave. Castroviejo is one of the best-known viewpoints and spots in the Urbión area and is often mentioned in local nature guides and routes in Soria. The visit is especially interesting in the rainy season, winter or thaw, when the waterfalls have more flow and the contrast with the rock and pine forest is greater. It is a highly valued place to walk calmly, observe geological forms and combine the visit with other nearby landmarks of the source of the Duero.
