The little we know about Atlantis is due to what Plato wrote. Plato wrote about the creation of Atlantis, his connection to Poseidon/Neptune, the fact that in this island there were all kind of animals and trees, that the people who lived there were more advanced than one could have possibly imagined and that greed or moral corruption drove Atlantis and its people to its/their demise.

Plato provides a detailed description of how the island was organized or structured and is also very specific as to where it should be located.

Blavatsky, in her Secret Doctrine (1888), complained about the fact that people were keen to believe in some of the formidable events described in the Old Testament yet regarded Plato’s account of Atlantis as purely fictional — which is basically what happened to Troy until Schliemann managed to find it…

But in spite of Blavatsky’s complaints, explorers (and scientists) have never given up the hope to find Atlantis. Unsurprisingly, various authors have attempted to provide Atlantis’ ultimate identification–it’s believed by some to be in West Africa, in Mauritania, in the Gulf of Guinea, in the Caucasus, in Central Asia, and in the Atlantic Ocean close to what are now the Azores.

Some scientists, however, are trying to collect the evidence that Atlantis’ real location is in Indonesia, in the Java Sea, to know more about it see: Atlantis in the Java Sea | A scientific effort to match Plato’s narrative location for Atlantis

References:

Blavatsky, Helena Petrovna, and Boris De Zirkoff. The secret doctrine. Vol. 2. Theosophy Company, 1888.