Santorini (Greek: Σαντορίνη, pronounced [sandoˈrini]), classically Thera (English pronunciation /ˈθɪərə/), and officially Thira (Greek: Θήρα [ˈθira]), is an island in the southern Aegean Sea, about 200 km (120 mi) southeast of Greece's mainland. It is the largest island of a small, circular archipelago which bears the same name and is the remnant of a volcanic caldera.