The castle of Koules, remarkable in terms of architecture, is closely connected to the history of the area and the memories of the local people. The castle consists of a large inner yard, enclosed all along the western side by two adjoining spaces linked with arches. Those spaces are roofed with domes. At the eastern part, there is an edifice, which is also roofed with a dome that lies lower than the other two, all along that side. It is accessible through a ramp on the southern side. The fortress was built of local whitish stone and hard connecting mortar. Both inside and outside it is coated and the thickness of the masonry is 1,20 m. The western and eastern edifices have collapsed. There is a cistern for the collection of rainwater, whose internal hydraulic limestone has been preserved.