Santorini is essentially what remains of an enormous volcanic explosion, destroying the earliest settlements on what was formerly a single island, and leading to the creation of the current geological caldera. Its spectacular physical beauty, along with a dynamic nightlife, have made the island one of Europe’s tourist hot spots.

Photo from Fira, Santorini, Greece

A giant central lagoon, more or less rectangular, and measuring about 12 km by 7 km (8 mi by 4 mi), is surrounded by 300 m (984 ft) high steep cliffs on three sides. The 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 merges with the sea in two places, in the northwest and southwest. The water in the centre of the lagoon is nearly 400 m (1300 ft) deep, thus making it a safe harbour for all kinds of shipping. The island’s harbours are all in the lagoon and there are no ports on the outer perimeter of the island, and the capital, Fira, clings to the top of the cliff looking down on the lagoon.