Built between the 8th and 13th century, the Castle of Silves (Castelo de Silves) is one of the best preserved of the Moorish fortifications in Portugal.

The castle consists of an irregular polygon implanted on a hilltop overlooking the community of Silves, comprising four towers and seven crenellated posts, linked by walls with ardaves.

Two gates, the principal one between two towers and the Traitor’s Gate carved into the northern wall. Alongside the principal gate is the guardhouse, constructed with a vaulted ceiling, and covered in tiles.

Within its courtyard are various subterranean structures, with accesses at soil level. The Cistern of Moura, is a 10 metres (33 ft) high, 820 square metres (8,800 sq ft) superficial area, with five naves marked by four orders of columns, interlinked by semi-circular archways. The Cisterna dos Cães, within the courtyard, is a vertical hole of 60 metres (200 ft) depth, that also supported water supply in the castle.

On the second floor of the Governor’s residence, there are two halls covered in painted wood. One of these halls includes a painting of royal arms, framed in shells and acanthus leaves, while on the four lateral panels, are military “trophies” comprising suits of armor, flags, lances, canons, muskets and drums. In the other hall is an allegory of Mars flanked by figurative and floral medallions.

In the military square, and alongside the southwest wall, are the vestiges of a house, presumably the residence of Prince Henry (when he was the alcalde of the Algarve), that includes foundations in dirt, a stone staircase (with a sigle on one flight), a spacious living room with the remains of a vaulted ceiling, olive oil press and pesto.