The Caldera of Santorini is the largest in the world, reaching 16 km in diameter. It was formed circa 1700 BC, after the “Minoan eruption” of Santorini’s volcano.
 
Its name comes from the spanish term “caldera” which means “cauldron” and is used to describe the cauldron-like depression that forms when a part of a volcano collapses. The Caldera of Santorini is surrounded not only by the island of Thera but another two , Therassia and Aspronissi. In its center, lie the volcanic islets of Palaia Kameni & Nea kameni.
 
At the top of the Caldera, some of the island’s most famous villages are built: Oia, Imerovigli, Fira and Firostefani.