Castillo de Curiel de Duero

Curiel de Duero, Spain, Spain

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Castillo de Curiel de Duero crowns a rocky hill in the Valladolid village of the same name, Spain, marking it as the province's oldest fortress with origins tracing to a Roman castellum and 9th-century masonry walls.

This medieval stronghold, featuring a square layout with four corner towers and a prominent keep, served as a key defensive bastion during the Reconquista's Duero Valley repopulation from the 9th to 11th centuries, owned by Castilian-Leonese monarchs like Alfonso VIII and used as a noble prison for figures such as Jaime IV of Mallorca.

 A popular saying notes its strategic dominance—"Peñafiel would be a fine castle if not overlooked by Curiel's"—and today it's restored as a luxury hotel-restaurant with panoramic views, surrounded by a once-extensive walled enclosure.