The Castle of Cola is an Iron Age hillfort that was later reinforced as an Islamic fortress in Portugal’s Alentejo region, now classified as a National Monument. It forms the centre of the Castro da Cola archaeological park, which features Megalithic, Chalcolithic, Bronze, and Iron Age remains. The polygonal fortification, with thick walls, a towered entrance, and a rock-hewn cistern, was strategically positioned to guard a key route into the Algarve.