I think I was referring to the black sea as well. Looking at my globe right now, which still has Soviet Union written on it, it does make more sense for the black sea to be the candidate.
A hundred fifty years ago, I saw a program on the discovery channel about artifacts found at the bottom of the black/dead sea which either could have been brought there by ship wreck or that a civ was once there.
I am not saying that a mountain range collapsed and a wall of water descended on these people. I'm saying that for all we know what used to be a desert could turn into a pond, then a lake, then a sea in a time span of years.
Now, imagine if you're a trader who have been away from home for many years. When you return to your homeland, you see a great body of water where there used to be a city. Even though it took like 5 years to flood the area, someone like you who wasn't there to see it would have thought, "wow, that was a really big flood."
Over the years, oral tradition turned into myth. And what happens when a person tells a story to someone else and that someone tells the story to someone else and so on and so forth? The story gets changed. Details are exaggerated to make it more interesting. Characters are added to traumatize the situation. After several centuries of this, you can pretty much guess what happens to the original boring story of the great flood that swallowed up a city or two.
This reminds me of Homer's story the Iliad. They've unearthed what they're pretty sure to be the city of Troy and they've discovered evidence that the city was once under seige and that there was a fire that destroyed it afterward. Even though the area was colonized by Alexander the great and then the romans who built layers upon layers of buildings on top of the old city, much evidence was saved.
But to the point, the Iliad is filled with magical beings and gods and goddesses. What if it was based on a real war but then centuries of oral tradition have changed it so much that starting from the original boring war you end up with a war that involved supernatural beings?