On the tranquil banks of the Drinos river 10km north of Gjirokastra, the ruined fortress near Paleokastra village is one of the few Roman military structures in the Balkans. Built around 300 CE for Constantine the Great's army, it served as a refuge and to guard the entrance to the Drinos valley The shape of the castle with its straight walls and corner towers is clearly visible, and as it's just a few minutes drive from the main road, it's an easy stopover.