Atlantis
Atlantis is a lost island civilization of Earth mentioned and described in two dialogues of Plato, Timaeus and Critias. These two dialogues are the only sources we have for this myth. According to Plato, who cites Solon the Lawgiver as his source, Atlantis was a large island in the "Atlantic Sea" somewhere beyond the Pillars of Hercules. The Atlanteans originally were a virtuous race, but later erred from the path of virtue and attempted to conquer the entire Mediterranean world, getting involved in a war with Athens and Egypt. The gods punished Atlantis by destroying the island, which is said to have happened 9,000 years before Solon's visit in Egypt where he received the tale.
Most scholars now think that Plato simply made up the tale; but many (both serious academics and amateurs) have sought Atlantis in many different locations, some blatantly implausible, others reasonably conceivable. A popular image is that of a lost continent in the middle of the Atlantic Ocean, but geological evidence speaks against that, and it is not certain whether the "Atlantic Sea" of Plato's tale can be simply equated with what is now called the Atlantic Ocean. Other popular ideas, though entirely unsupported by the source, are that Atlantis was the "mother culture" of all ancient civilizations of Earth, and that it possessed technology and scientific knowledge far superior to that of the early 21st century. Also, it has been speculated that Atlantis was the same place as Hyperborea, another legendary country of Greek mythology.
The most frequently discussed of the less implausible localizations equates Atlantis with the Minoan civilization and the fall of Atlantis with the eruption of the Santorini volcano; however, the Minoan civilization was obviously not "beyond the Pillars of Hercules", and the years elapsed after the catastrophe would have to be divided by 10 (perhaps a translation error?).
It is also sometimes assumed that the Atlantis myth reflects the incursions of the Sea Peoples around 1200 BC, which caused the downfall of the Hittite Empire and of the Mycenean civilization in Greece.
Jörg Rhiemeier speculates that in the Atlantis tale, the downfall of the Minoan civilization was just one component Plato drew upon; another were the Sea Peoples invasions, and yet another was the story of another civilization, the Elves of prehistoric Britain. Atlantis would then have been Britain, and the "Atlantic Sea" the North Sea.
Atlantis has been the subject of many novelizations and media adaptations, such as the 2001 animated film Atlantis: The Lost Empire, which features a conlang. Another famous Atlantis adaptation is Númenor in The Silmarillion by J. R. R. Tolkien, which features another conlang.
