a series of travel images from Greece, Santorini (officially Thira) is a volcanic island in the Cyclades group of the Greek islands in the southern Aegean Sea, about 200 km southeast of mainland Greece. An enormous volcanic explosion somewhere around 1500 BC created the current geological caldera. Thira is famous for its dramatic views, the whitewashed houses of the towns of Fira and Oia offer many pleasant places to stay for the visitor.