The Torcajón Sinkhole Nature · Casarejos, Pinares, Soria Image of Casarejos, not of the place itself. The residents give this name to a notable sinkhole opened in the limestone ground of the municipal district, which also takes part in the Cañón del Río Lobos with 156 hectares and in a bird protection zone of 644. Photo: Wamba Wambez (CC BY-SA 3.0) What to see and do in Casarejos