Why it matters
A vast concentric dome in the desert, matching a few of Plato's measurements — which is why it draws the eye. We mark the resemblance as suggestive, the geology as the leading reading.
What mainstream says
A deeply-eroded geological dome, not a built or drowned city. The Atlantis match is selective. Grade: contested.
The memory of it
The Richat Structure — the 'Eye of the Sahara' — is a forty-kilometre concentric dome in the Mauritanian desert that draws attention because a few features loosely match Plato's Atlantis: concentric rings, roughly the right scale, mountains to the north. We mark the resemblance as suggestive and the geology as the leading reading (grade C). It is almost certainly a deeply-eroded geological dome, not a built or drowned city, and the Atlantis 'match' is selective. So why keep it? Because it is a clean example of how the mind finds patterns where it wants them — and the honest move is to state both the resemblance and the far more likely natural cause, then let you decide. It sits on the forbidden shelf as a labelled question, not an answer.
Sources & further reading
The authoritative reference for this site/finding — and its own primary citations — so you can check us.