text: The Cave of El Castillo is one of several caves containing Palaeolithic art in the municipality of Puente Viesgo in Cantabria, Spain, situated some 20km southeast of the more famous cave at Altamira. Discovered in 1903 by Hermilio Alcalde de Río, the cave contains several chambers in which friezes of paintings are located, and there is evidence to suggest the cave was in intermittent usage from the Auriginacian until as late as the Bronze Age, and that during the Magdalenian may have formed, along with Altamira and other nearby caves, the core territory of a single human group. Indeed, there are several smaller Palaeolithic painted caves within the same mountain as El Castillo, and the area may have formed a key pilgrimage or sacred site for this group.