That does not make the existence of Atlantis a mere fiction.
With the end of the Ice Age and its consequences, plenty of civilizations may have disappeared in deep waters. The Sumerians themselves claimed they received their knowledge from a man who visited them by the sea (fish-man like creature) on the aftermath of the great flood which may have buried plenty of Atlantis-like civilizations which could be the missing links to understand how, for instance, the Egyptians built the pyramids.
With the end of the Ice Age and its consequences, plenty of civilizations may have disappeared in deep waters. The Sumerians themselves claimed they received their knowledge from a man who visited them by the sea (fish-man like creature) on the aftermath of the great flood which may have buried plenty of Atlantis-like civilizations which could be the missing links to understand how, for instance, the Egyptians built the pyramids.