From Bulbapedia, the community-driven Pokémon encyclopedia.
Pokélantis (Japanese: ポケランティス Pokélantis) is a lost empire located in the proximity of Pewter City. It is only mentioned in the Pokémon anime in Battling the Enemy Within.
In the present day, all that remains of the once-thriving city is the tomb of the king who once ruled it. Ho-Oh destroyed the city because the King wanted to use the legendary Pokémon's powers to rule the world. It was said that the King trapped Ho-Oh in a stone orb and then ran off.
Brandon decided to investigate what ultimately led to the discovery of the tomb, which is baited with many traps. While on their way to the Battle Pyramid, Ash and his friends accidentally stumbled upon the site. He hears about the story of Pokélantis from Brandon and decides to look for the orb containing Ho-Oh so he can battle it. He soon discovered that the orb did not contain Ho-Oh, but the spirit of the King, who possessed Ash with the intent of taking over the world and rebuilding Pokélantis. According to Brandon, the King chose Ash's body for his carelessness and arrogance.
Eventually, Brandon was able to seal the King's spirit back into the orb and return it to what remains of Pokélantis.
- The name of this city is derived from Atlantis. Its name is made by joining "Pokémon" and "Atlantis".
- Pokélantis is one of two known ancient civilizations in Kanto. The other is Pokémopolis which happens to be in the same area.