Mu is a lost continent introduced by Augustus Le Plongeon, who identified the "Land of Mu" with Atlantis. The name was subsequently identified with the hypothetical land of Lemuria by James Churchward
Underwater structures claimed to be remnants of Mu, near Yonaguni, Japan
Lost lands are islands or continents believed by some to have existed during prehistory, but have since disappeared as a result of catastrophic geological phenomena.
Mu (mythical lost continent)
…Mu is a lost continent introduced by Augustus Le Plongeon, who identified the "Land of Mu" with Atlantis. The name was subsequently identified with the hypothetical land of…