According to ancient texts, the high Egyptian priest of Sais spoke to Solon about Atlantis, a continent that existed more than 10,000 years ago that was beyond the Pillars of Heracles, or as we know him Hercules, which is now considered to be Gibraltar. Was it Gibraltar? Not really sure. Scientists only guess at the actual location. The pillars might just have disappeared in some earth quake or global catastrophe.
The Timaeus dialogs, a speech or dialog by Plato, placed the island in the Atlantic Ocean. The initial idea was that Atlantis was somewhere between Europe and America, though many other suggestions have been proposed, some of which place Atlantis in Antarctica, Greece and Indonesia.
I can see Atlantis being out in the Atlantic Ocean. It was beyond the Pillars of Hercules. How some folks come to decide it was anywhere around Greece is beyond me since Greece is in the Mediterranean and not past Gibraltar. Of course if the pillars no longer exist they could have been anywhere.