Caves of Monte Castillo - Credit: Wikimedia Commons
The Caves of Monte Castillo, located in the Cantabrian town of Puente Viesgo, contain one of the most important Paleolithic sites in the region. The complex of karstic caves is on the slopes of Monte Castillo, a hill south of Puente Viesgo, with an elevation of . Read more on Wikipedia
Source: en.wikipedia.org