This episode investigates Atlantis, the legendary island that was supposed to have existed "beyond the Pillars of Hercules" (Straits of Gibraltar) and whether or not it really every existed. Plato's dialog on Atlantis is discussed as well as the possible locations of Atlantis. Was it near the Bahamas, was it in the Mediterranean itself, or was it the ancient island of Santorine, that was blown into oblivion by a volcanic eruption? Scientist discuss underwater archeology of the region and that of the Bahamas and historians debate the historical accuracy and validity of Plato's dialog on the legendary island.