Santorini, known as Thera, was later converted to Santorini in 1207 in memory of Saint Irene. Santorini is an island ring of volcanoes in the Aegean Sea 200 kilometers southeast of mainland Greece, the largest island on the ring is also called Santorini, alias Thira. Santorini is located at the southernmost tip of the Cyclades Islands (Cycladesislandcomplex), with an island area of 96 square kilometers and a coastline of 69 kilometers, with a population of about 14,000 people, mostly Greeks. Santorini is composed of three small islands, two of which are inhabited, and the middle of the island is a sleeping volcanic island. Historically, there have been many volcanic eruptions, the most serious in 1500 BC, the center of the island collapsed, the original round island appeared to be crescent-shaped. Santorini's capital is the city of Ferra, located on the west bank of the island.