ding, like I think you said, ancient man didn't know the "whole" world, only his neck of the woods. It seems to be pretty established theory that the coastal areas around the Mediterranean and Black Seas flooded at the end of the last ice age due to a big rise in the Atlantic Ocean, from melt water. If this Hiawatha crater is what they think it is, it may have done the deed, but I don't think it necessarily flooded the whole world, ding. All of the earliest civilizations grew up around seas or river systems, for obvious reasons. Over time, they would have all flooded but I don't think every flood that was spoken of by ancient man happened at the same time. A rise in the Atlantic Ocean would not have caused a flood in India or China, I don't think anyway.