Castillo medieval de Almadén de la Plata Monument · Almadén de la Plata, Sierra Norte, Seville Image of Almadén de la Plata, not of the place itself. Fortress built around 1350 on a 1st-century Roman hillfort, belonging to the medieval frontier zone known as the Banda Gallega. Declared a Bien de Interés Cultural on 25 June 1985, Spain's highest level of heritage protection. BIC desde el 25 de junio de 1985 Photo: Pjmmacarro (CC0) What to see and do in Almadén de la Plata