A church with blue dome in Santorini (Thira) member of the Cyclades group of islands, Aegean sea, Greece.
Santorini (Greek: Σαντορίνη, pronounced [sadoˈrini]), officially Thira (Greek: Θήρα [ˈθira]), is an island located in the southern Aegean Sea, about 200 km (120 mi) southeast from 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. It forms the southernmost member of the Cyclades group of islands, with an area of approximately 73 km2 (28 sq mi) and a 2001 census population of 13,670.
The municipality of Santorini is composed of the inhabited islands of Santorini and Therasia and the uninhabited islands of Nea Kameni, Palaia Kameni, Aspronisi, and Christiana. The total land area is 90.623 km2 (34.990 sq mi). Santorini is part of the Santorini peripheral unit.
Santorini is essentially what remains after an enormous volcanic explosion that destroyed the earliest settlements on what was formerly a single island, and created the current geological caldera. A giant central lagoon, more or less rectangular, and measuring about 12 by 7 km (7.5 by 4.3 mi), is surrounded by 300 m (980 ft) high steep cliffs on three sides.
The main island slopes downward from the cliffs to the surrounding Aegean Sea. On the fourth side, the lagoon is separated from the sea by another much smaller island called Therasia; the lagoon is connected to the sea in two places, in the northwest and southwest. The water in the centre of the lagoon is nearly 400 m (1,300 ft) deep, thus making it a safe harbour for all kinds of shipping.
The island’s harbours all lie in the lagoon and there are no ports on the outer perimeter of the island; the capital, Fira, clings to the top of the cliff looking down on the lagoon. The volcanic rocks present from the prior eruptions feature olivine and have a notably small presence of hornblende.