Atlantis (lost continent)
Atlantis is a mythical lost continent on Old Earth. According to Plato a great continent in the Atlantic Ocean, and the civilization inhabiting it; destroyed in a terrible catastrophe. Plato may or may not have intended the account to be read as a fictional cautionary tale rather than as history. The meme was revived during the Industrial Age, and both genuine and pseudo-archaeologists speculated on the existence of this island, which has been variously located in Thera near Crete, and also in the Azores, the North Sea, and elsewhere, its destruction (perhaps by a volcanic eruption) being used to explain a large number of deluge stories in the myths of Mediterranean peoples.
In Theosophical, Nuage, post-theosophical, and some Pleiadeanist memeticities and religions Atlantis became the fourth great land-mass or continental system of Old Earth which existed several million years ago, and which was the home of the fourth root-race, (evolving from the Lemurian Third Race). Hence Atlanteans. There is absolutely no scientific evidence for such a place as described by theosophical and nuageist memeticities, but the myth persists among certain baseline-equivalent groups nevertheless.