From Bulbapedia, the community-driven Pokémon encyclopedia.
Pokélantis (Japanese: ポケランティス Pokélantis) is a lost empire in the proximity of Pewter City. It is only mentioned in the Pokémon anime in Battling the Enemy Within.
In present day, all that remained of the once thriving city was the tomb of the king who once ruled it. Ho-Oh destroyed the city because the king wanted to use its 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 which ultimately led to the discovery of the tomb, which is baited with many traps. While passing through the area, 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. But the orb didn't contain Ho-Oh, but the spirit of the king, who possessed Ash, intending to take over the world and rebuild Pokélantis.
Eventually Brandon is able to seal the king's spirit back into the orb and returns it to what remained of Pokélantis.
- The name of this city is derived from Atlantis.
- Pokélantis is one of two known ancient civilizations in Kanto. The other is Pokémopolis which happens to be in the same area.