Manzanares el Real Castle, a gem of civil architecture overlooking Santillana dam, was erected in the 15C in the Isabelline Gothic style by the duke of the Infantado. It follows a square plan with a lovely central courtyard and massive walls, whose severity is softened by a line of pearls around the turrets. Juan Guas was, among others, the author of the first floor Gothic gallery, felt to be the most stunning part of the castle.