Atlantis was an island that used to thrive by the pillars of Hercules. The myth of Atlantis was first mention in Plato's dialogs timaeus and critias.
Atlantis was said to be larger than Libya and Asia combined. Plato mentioned that it was formed in circular belts of sea and land, enclosing one another. It was said that great bulls used to roam the temple's of Atlantis.
The island itself was first found by Poseidon. Afterwards it was ruled by his ten sons till the very tragic day Atlantis was destroyed in a great flood. Before that Atlanteans were very peaceful people, but with time going on they all became greedy and corrupt as in result began taking over the world. After a failing attempt to invade Athens, gods decided to punish Atlantis for it's crimes and in a single day and night the island was destroyed.
The rulers of Atlantis were the ten sons of Poseidon. Each one of them ruled a part of Atlantis, but greatest city on the island was ruled by Atlas.
Atlantis is said to lay beyond the Pillars of Heracles.