Since time began, people have always searched for their origins. There are three famous lost lands that are often referred to as the origin of the current races of people - Atlantis, Lemuria and Mu.
Lemurs are only found on the island of Madagascar. In the 1800s Lemur fossils were found in both Madagascar and in the Indian sub-continent, but not in Africa or the Middle-East. For the scientists of the time, the only logical explanation s that Madagascar and Indian were once joined together through a lost, now sunken continent - they named it Lemuria.
Later when the field of geological plate tectonics was created, the concept of a sunken continent lost favor. There is no evidence that any sort of geological upheaval of a lost continent in either the Indian of Pacific oceans. Even though science indicated that the existence of Lemuria was not probable, it did not mean that Lemuria was forgotten.
In the 1880s the famous mystic/occultist, Madame Blavatsky described Lemuria and claimed it had a great civilization which died out. It is sometimes claimed that Mount Shasta in California is the last remaining outpost of Lemuria.
Even though scientific evidence seems to point to the fact that there was no Lemuria and the claims of Madame Blavatsky are generally considered to be at best creative, this is just another piece of evidence that there may have been other civilizations before out recorded history. Remember, Troy was just a legend until is was found.