Santorini, is an island in the southern Aegean Sea, about 200 km 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. The municipality of Santorini includes the inhabited islands of Santorini and Therasia, as well as the uninhabited islands of Nea Kameni, Palaia Kameni, Aspronisi and Christiana. The total land area is 90.623 km2.
The island was the site of one of the largest volcanic eruptions in recorded history: the Minoan eruption, which occurred about 3,600 years ago at the height of the Minoan civilization. The eruption left a large caldera surrounded by volcanic ash deposits hundreds of metres deep. Another popular theory holds that the Thera eruption is the source of the legend of Atlantis.