San Cibrao de Las hill fort (Castro de San Cibrao de Las) is a hill fort of the so-called castro culture. Rather than a single castle, it encompasses an entire fortified town or village. The place was inhabited from the second century BC to the second century AD. It flourished during the first century, at the beginning of Roman rule in Galicia.
The ruins are located on a 473-metre-high hill, covering an area 384 m long and 314 m wide. Unlike the other hill forts of the area, there are many straight walls and fewer curving structures.
References: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.