A Cava de Viriato

The camp has an octagonal shape, bounded by strong slopes, with 2000 meters of perimeter and an area of eight hectares; on the east, north and west faces it shows traces of a moat. Of the eight slopes, six remain. According to Jorge de Alarcão, the rammed earth wall has a trapezoidal profile, about 27.5 meters wide at the base and six meters on the crowning platform, with an internal surface of thirty hectares.
The Cava was traditionally considered a Roman-era camp, built by Décimo Júnio Bruto Galaico (137–136) or, according to Jorge de Alarcão, by the military chiefs Petreio and Cássio Longino in the middle of the first century BC. it is defended by a moat that the waters of the river Pavia and the stream of Santiago flooded. More recently, Vasco Mantas, despite considering that a Roman camp existed in the Cava area, attributes its construction to the Arabs.