there are hundreds of very similar stories told by different nations around the world.
I see this claim a lot on the Net, yet it is never supported. So, perhaps you can point us to a few stories from around the world that are 'very similar' to the Bible version.
I my experience, the flood stories from around the world differ greatly from each other, and especially the two flood myths in the Bible.
Look at some of the Phillipino flood myths, they are nothing like Noah's adventure.
Then, of course, there are many nations who do not have a flood myth.
Finally, we have the archaeological record that falsifies the biblical flood.
A worldwide flood as described in the Bible has been demonstrated to be untrue by every investigative discipline that we have.