"So thar we were, battlin' the mighty whirlpool for nigh on a full moon, when with a great plop we plunged twenty fathoms down into the depths. But nay, to our surprise we did not die (bar Cannonball Jack, who got etted by a shark), and found ourselves in a strange city full o' golden treasure. Took it all, we did, but pursued we were, by creatures, half men, half fish, half plant. But we fled away, to live and fight another day!"
The name is derived from Charybdis, a whirlpool in Greek mythology, and Atlantis (obviously) =P