Atlantis is a legendary island in the Atlantic Ocean. The name is also sometimes spelled Atalantis or Atlantica. The first mention of Atlantis came from Greek philosopher Plato. He wrote about the island in the dialogues the Timaeus and the Critias (both written about 360 bc). The dialogues contain conversations between two or more groups of people. In these works a character describes what he knows about Atlantis. The information, he says, was passed down from ancient Egyptians. According to this account, Atlantis was an island larger than Asia Minor (roughly modern Turkey) and Libya combined. It was located beyond the Pillars of Hercules, two rock formations at the eastern end of the Strait of Gibraltar (the channel connecting the Mediterranean Sea with the Atlantic Ocean). Atlantis was a rich island whose powerful princes conquered many of the lands of the Mediterranean. However, the Athenians eventually defeated the princes and their allies. The people of Atlantis then grew wicked and disrespectful. About 9600 bc a series of earthquakes struck, causing the island to fall into the sea.

Most scholars believe that Atlantis was a legend that Plato created. Throughout time, however, some people have tried to prove that Atlantis was real. Medieval European writers heard the tale from Arab geographers and believed the story. After the Renaissance various people attempted to identify Atlantis with America, Scandinavia, and the Canary Islands. The story of Atlantis—if Plato did not invent it—may reflect ancient Egyptian records of a volcanic eruption on the island of Thera about 1500 bc. This eruption was one of the greatest in historical times. It was accompanied by a series of earthquakes and tsunamis that shattered civilization on Crete. This historical occurrence may have given rise to the legend of Atlantis.