Castro Marim Castle

No doubt the Castle (Castillo) is the signature building of the small Portuguese town of Castro Marim and is a National Monument in Portugal. It's medieval, built in the thirteenth century (although there are structures dating back to the Bronze Age) on a hill overlooking the mouth of the Guadiana. It has an irregular quadrangular shape, defined by 4 semicircular cubes in each corners and a courtyard with 2 entrances (north and south). It was part of a fortress and defended by a wall, within which was the castle itself, the Church of Mercy and other buildings now in ruins (the church of Santiago, the Santa Maria, the magazine, etc.).