Plato (c. 424–328 B.C.) describes it as a powerful and advanced kingdom that sank, in a night and a day, into the ocean around 9,600 B.C. The ancient Greeks were divided as to whether Plato's story was to be taken as history or mere metaphor.

According to the primary historical source, the Greek philosopher Plato, Atlantis was a formidable naval power that "in a single day and night of misfortune" sank into the ocean around 9,000 years before his time. In his dialogues Timaeus and Critias, Plato describes the island as situated beyond the "Pillars of Hercules" (the Strait of Gibraltar). However, modern geologists and oceanographers have found no scientific evidence of a sunken continent in the Atlantic that matches this description. Most scholars today categorize Atlantis as a philosophical allegory—a fictional "thought experiment" used by Plato to illustrate his theories on the ideal state versus hubris and corruption. While some theorists suggest the legend was inspired by real cataclysms, such as the Thera eruption that devastated the Minoan civilization on Crete, the literal city of Atlantis as a sunken high-tech metropolis remains a captivating myth rather than a verified historical or geological event.