The Ruinas del Castillo del Collao is a medieval fortress perched on a hilltop in Camargo, Cantabria, dating to the 8th–12th centuries. Once the largest of approximately thirty similar fortifications in the region, this early medieval stronghold occupies a strategic position overlooking the Bay of Santander and surrounding valleys. The castle is encircled by a robust limestone wall over 2.5 meters thick, encompassing an area of 512 square meters. Declared a cultural heritage site in 2003, the castle underwent archaeological excavations and stabilization efforts, and remains accessible to visitors seeking insights into Cantabrian medieval history.
