Poseidon Builds an Island of Rings
Out past the Strait of Gibraltar lies a huge island, and the sea god Poseidon carves its centre into rings of land and water.
Before the war, in an age Plato places more than 9,000 years before Solon
What the text says
This power came forth out of the Atlantic Ocean, for in those days the Atlantic was navigable; and there was an island situated in front of the straits which are by you called the Pillars of Heracles; the island was larger than Libya and Asia put together
Timaeus 24e
And Poseidon, receiving for his lot the island of Atlantis, begat children by a mortal woman, and settled them in a part of the island, which I will describe.
Critias 113c
there were two of land and three of water, which he turned as with a lathe, each having its circumference equidistant every way from the centre, so that no man could get to the island, for ships and voyages were not as yet.
Critias 113d-e
the eldest, who was the first king, he named Atlas, and after him the whole island and the ocean were called Atlantic.
Critias 114a
The story
In the first days, the gods divide the earth among themselves. Poseidon, god of the sea, receives a great island in the ocean beyond the Pillars of Heracles. Plato says it was bigger than Libya and Asia together, which for a Greek meant North Africa and the lands to the east.
On a low hill near a wide plain lives a young woman named Cleito, whose parents have died. Poseidon falls in love with her. To protect her home, he cuts rings around the hill: two rings of land and three of water, perfectly round, as if turned on a potter's wheel. No one can reach the centre, because no one has ships yet.
Poseidon brings up two springs at the centre, one warm and one cold, and makes food grow. Cleito has five pairs of twin sons. Poseidon splits the island into ten parts, one for each son. The eldest, Atlas, becomes the high king, and the island and its ocean are named after him.
Plato does not say what Cleito thought of all this, or how long the ten brothers lived. He lists the names of all ten, then moves straight on to their wealth.
The Pillars of Heracles was the Greek name for the two rocks on either side of the Strait of Gibraltar, so Plato puts Atlantis in the Atlantic Ocean. The Atlantic sea floor is young rock that forms along the Mid-Atlantic Ridge and slowly spreads apart, and plate tectonics rules out a lost continent sinking there in the recent geological past. Some people online point to the Richat Structure in Mauritania because it has rings; geologists explain it as a worn-down dome of rock shaped by erosion, and it sits on dry land, not in the sea.