atlantis I personally believe did exist but just as a slightly more advanced
civilization.
There are even a few good documentaries that suggest a few
different locations as possible origins of the atlantis story.
There are many places we thought to be naught but fantasies
that have now been found and proven to exist like the 5 cities
of the plain or Troy.
Atlantis could very well have existed but there is very little information to go
by that is not surrounded by myth & legend.
We are constantly finding new things that force us to redate time periods
and change or views on ancient societies that you never know what
the next discovery will be.