Athanasius Kircher's map of Atlantis, here seen in the middle of the Atlantic Ocean. The map is oriented with south at the top.

Atlantis is a name for a fictional large island or small continent that was in the Atlantic Ocean many years before it sank into the depth of the sea.

The name Atlantis first appears in the writings of Herodotus - he describes the western ocean as "Sea of Atlantis." Then, one generation later, Atlantis is described in detail in the stories Timaeus and Critias by the Greek philosopher Plato. He used this story to help explain his ideas about government and philosophy. Plato was the only ancient writer who wrote specific things about Atlantis.