My pick
My tip“One to two hours. Entry to the courtyard is free, and the guided tour of the tower is by ticket (book in advance, in Spanish). Large free car park.”
A 15th-century brick castle with a deep moat and a towering keep, linked to Queen Isabel la Católica and used as a royal prison. 45 min south of Valladolid.
Address
Av. Castillo, s/n