Atlantis (at-LAN-tis). According to the philosopher Plato, an advanced civilization that sank beneath the waves, a legend based perhaps on Minoan Crete. The fabled island-continent derives its name from the Titan Atlas. It was said to be out beyond the western headland where the immortal giant holds up the heavens by means of a pillar on his back. Plato maintained that Atlantis was a real place, not a myth. He in turn had heard of it from certain wise men of Egypt, whose civilization spanned the era when Atlantis was said to have flourished, whereas earlier civilizations in Greece had been wiped out by natural catastrophes - or so the Egyptians said. Plato's description of Atlantis bears pronounced similarities to the Greek island of Crete as it must have been during the heyday of the Minoan culture. And whereas Atlantis was supposed to have sunk beneath the waves, Minoan Crete succumbed to the monumental volcanic eruption of the neighboring island of Thera - which may well have been accompanied by a huge tsunami, or tidal wave.