Alexander, George S., and Rosen, Natalis
George S. Alexander and Natalis Rosen have established a website(a) promoting the Richat Structure, in Mauritania, as the location of the city of Atlantis. They are not the first to make this suggestion but have at least visited the site in 2008 to gather evidence to support their contention. Their expedition formed the basis for a free one hour video(b). Like supporters of various other locations theories, Alexander and Rosen have managed to match some of the details in Plato’s description with features in the Richat area.
The Richat Structure is around 35km in diameter yet no evidence of buildings whatsoever was found. In my opinion Alexander & Rosen have not satisfactorily explained this absence. Apart from that a city with a diameter of 35km is not credible in the timeframe proposed by them.