Mrrzy...they HAVE done some underwater exploring in the Black Sea and discovered artifacts and an ancient 'shoreline'. It is almost undisputed now that The Bosphorus was once a barrier to the sea, and that it allowed huge changes at one time. Whether it was 'catastrophic' is being debated, but all it would take is ONE major event to start a legend. What IS clear is that there was never enough water to cover 'everything' on Earth, and that legends must be interpreted in terms of who promulgated them...& when.