The current name of Santorini archipelago came up in times of a Latin empire in the 13th century by Saint Irene (Irene Sancta). Earlier names archipelago sounded Kallístē, Strongýlē or Thēra.
Present the rest of the archipelago is a large volcanic island (called at the time therm), the center of which was thrown a huge explosion , after which the island remained a peripheral portion surrounding up to 400 m deep lagoon . It has an oval shape with dimensions of about 17 km from the northwest to the southeast and a width of 13 km. The main and by far the largest island, tied round arch all the north, east and south of the archipelago is Thira, in the northwest of the island of parallel forms Thirasia and closed circuit on the west island Aspronisi. In the middle between the two islands is Kaimeni Nea and Palea Kaimeni. While from the outside, the surface rises gradually from the coast, towards the inside of the lagoon fall into the sea from 200 to 300 m high cliff. The total area is 71 km ² and the highest peak Profitis Ilias towers 567 m above sea level. The archipelago has about 10,000 permanent residents and is a major center of tourism.
The volcanic eruption that destroyed the original island of Thera, occurred sometime in the 17th century BC It is probably one of the most powerful volcanic eruptions known to man that his strength greatly exceeded the famous eruption of Krakatoa in 1883 (according to some estimates, up to 100 ×).
What the former island of Thera left, is currently called Santorini archipelago.