"According to Plato, Atlantis was a naval power lying 'in front of the Pillars of Hercules' that conquered many parts of Western Europe and Africa 9,000 years before the time of Solon, or approximately 9600 BC. After a failed attempt to invade Athens, Atlantis sank into the ocean 'in a single day and night of misfortune'." (Wikipedia)Legend has it, the lost city of Atlantis is the sunken, underwater, caldera of Santorini.
Whereas most calderas are the highest point of a volcano, Santorini's caldera (12 by 7 kilometers or 7.5 by 4.3 miles) mysteriously, and quite suddenly, collapsed. Coincidence? I think not.