In this video, made by Nicos Korakakis, the geographical history of Santorini is depicted. The island, which had been formed 30,000 years ago, was double in size compared to its modern state. Almost 25,000 years ago, the island’s volcano erupted and formed the caldera, sinking almost half of the island. In 1614 BC, the volcano erupted again, and the explosion destroyed a large part of the Santorini, breaking it in three separate islands. The last eruption took place in 1950.
(The narration of the short video is in Greek, but the text is in english)
Modern Santorini is essentially what remains after an enormous volcanic eruption that destroyed the earliest settlements on a formerly single island, and created the current geological caldera. A giant central, rectangular lagoon, which measures 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 to the 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 depth of the caldera, at 400m, makes it possible for all but the largest ships to anchor anywhere in the protected bay; there is also a newly built marina at Vlychada, on the southwestern coast. The island’s principal port is Athinias. 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 small presence of hornblende.
You can also watch the video on the rich youtube channel History and Beauty of Planet Earth