Acropolis of an unwalled settlement at Chorio, on top of a hill fading the sea. There are two distinct phases of construction: Hellenistic and Hospitaller. Oblong in plan, it stands on ancient foundations. It covers an area of 3,600 square metres and the perimeter of the defences is 280 metres. The log sides, to north and south, end in two towers, one polygonal and the other rectangular in plan. The walls on the south side have collapsed, but they were not, apparently, particularly tall because the terrain is very steep and the site naturally defensible The north side is better preserved, with a wall-walk and the arms of grand master Pierre d? Aubusson (1476-1503). At the east end is the main gate and two small towers cover recessed parts. Inside the castle stands the ruined church of St. Nicholas, with vestiges of its mural decoration. In 1475 and 1480 the castle was evacuated, while in 1493 it was finally abandoned and the inhabitants of Chalki sought refuge in Rhodes. In 1522 the castle was occupied by the Ottoman Turks.