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.
According to Plato, the Atlanteans lived 9000 years before his own time and were half human and half god. They created a very good human society. When they stopped being good people and did bad things, the gods sent earthquakes and fire to destroy Atlantis.
Many scholars think Plato could have been thinking of a real place when he wrote about Atlantis. Many, many people have thought of many, many places where the real place that inspired Atlantis could have been. For example, there was a Minoan kingdom on the island of Santorini. The Minoan kingdom was very powerful thousands of years before Plato, and their society was damaged when a volcano erupted on their island. According to Plato, Atlantis was very large, as big as North Africa, so it should not have been hard to find.
After the discovery of the Americas, some people in Europe thought they might be Atlantis. However, after Plato, the idea of Atlantis was mostly forgotten until 1882, when a writer named Ignatius Donnelly wrote a book saying that Atlantis was real and that the culture of Atlantis had started many other ancient cultures, such as the Egyptian and Mayan. Then other people became interested in Atlantis. 
Atlantis has appeared in many works of fiction. In Marvel Comics, Atlantis is at the bottom of the ocean and exists in modern times, with people who breathe water. Other works of fiction use Atlantis as background. For example, Robert E. Howard set his Conan the Barbarian stories in a fictional time called the Hyborian Age, which began with the destruction of Atlantis and ended when real written history started.
- Willie Drye. "Atlantis: Plato created the legend of Atlantis. So why is it still popular more than 2,000 years later?". National Geographic. Retrieved September 6, 2020.
- Plato (n.d.) [360 BCE]. "Critias". Translated by Benjamin Jowett. Massachusetts Institute of Technology. Retrieved August 4, 2020.
- Geoffrey Giller (July 21, 2020). "Where Is the Lost City of Atlantis — and Does It Even Exist?". Discover Magazine.
- Zac Farber (May 30, 2018). "Ignatius Donnelly: Paranoid Progressive in the Gilded Age". Minnesota Lawyer. Retrieved September 6, 2020.
- "Conan the Cimmerian: Not the Barbarian You Remember". Carnegie Library. November 7, 2018. Retrieved September 6, 2020.
- Tim Dedopulos (August 6, 2019). "Howard's Hyborian Age". Conan Official Site. Retrieved September 6, 2020.