Santorini Caldera, Greece is an ancient volcano that has captivated visitors for centuries. Located in the Aegean Sea, the caldera is the result of a volcanic eruption that occurred in the 16th century BC. The
From Wikipedia
The Santorini caldera is a large, mostly submerged volcanic caldera located in the southern Aegean Sea, 120 kilometers north of Crete in Greece. Visible above water is the circular Santorini island group, consisting of the main island of Santorini, Therasia and Aspronisi at the periphery, and the Kameni islands at the center. It has been designated one of the world's sixteen Decade Volcanoes.