According to Plato, atlantis was "beyond the columns of Hercules", very close to the Canary Islands, once crossed the Strait of Gibraltar.

It was Plato, towards 360 B.C. the first and only one who left in writing the existence of the kingdom of Atlantis in his dialogues of Timaeus and Critias, when he described it as an extensive and flat island in the center of which was a hill, which in turn was surrounded by three concentric rings of the sea. At the top of the hill there was a temple dedicated to Poseidon and Cleitus surrounded by a wall entirely of gold. At his side, another temple of Poseidon was made of silver. Two sources were constantly pouring water, one cold and the other warm. In the nearest ring lived the richest and highest status of their society, and in the next ring the plebeians. Beyond an extensive meadow full of aromatic substances, to complete an island "even bigger than Asia Minor and Libya together" ...

https://www.taringa.net/posts/info/18130362/Grandes-misterios-sin-respuesta.html