Piedrabuena Castle is part of defense line of Guadina and Tajo rivers near Portugal border. The oldest parts date from the late 14th and early 15th centuries. It has been head of the Encomienda of the Order of Alcántara since the 13th century.
The exterior enclosure is a quadrangular construction with cylindrical towers at the corners. In the interior there are four corridors, the keep and the prison tower. The residential function of this building is easy to see, with galleries open to the outside and a cloistered patio, all in the manner of an urban palace.
Today Piedrabuena Castle is privately owned.
The Gravensteen is a castle in Ghent originating from the Middle Ages. The name means 'castle of the counts' in Dutch. Arnulf I (918–965), Count of Flanders, was the first to fortify this place, building a medieval bastion on this high sand dune, naturally protected by the river Leie and its marshy banks. This bastion consisted of a central wooden building and several surrounding buildings, also in wood.
In the early 11th century, the wooden building was replaced by a stone residence, consisting of three large halls that made up three storeys, connected by a stone stairwell. The monumental stone staircase, the light openings, the fireplaces built into the walls and the latrines were signs of considerable luxury and comfort in those days. There was probably also a tower.