There is a new proposal concerning Atlantis and its location going viral just now. The new theory is popularized by Bright Insight at YouTube, but was originally proposed by George S Alexander and Natalis Rosen. Their website is called Visiting Atlantis and an entire documentary about their discovery is available at the Gaia Network (unfortunately, not for free).
According to this scenario, Atlantis is identical to the Richat Structure, a peculiar geological formation in Mauretania, also known as the Eye of the Sahara or the Eye of Africa. I´m not sure if I buy this, since Mauretania is a landlocked country rather than an island, but the Richat is a weird formation in any case. Perhaps it proves that the Earth is ALIVE and sometimes plays pranks on us, crop circle style?