Oia Castle

Known as the Castle of Agios Nikolaos, these ruins sit on a headland above Oia's rooftops, at the point where the village runs out along the caldera rim. Built by the Venetians and largely lost in the 1956 earthquake, only fragments of wall remain, but the terrace in front of them is Santorini's best-known sunset spot: unobstructed views across the flooded caldera to Thirasia and the volcanic islets, with Oia's blue domes and cave houses stacked below. It fills up well before sunset in summer.