"Atlantis is the name of an island first mentioned and described by the classical Greek philosopher Plato. According to him this island, lying "beyond the pillars of Hercules", was a naval power, having conquered many parts of western Europe and Africa. Soon after a failed invasion of Athens, Atlantis sank in the waves "in a single day and night of misfortune" after a natural catastrophe happened 9000 years before Plato's time." (From Wikipedia.org)