From Bulbapedia, the community-driven Pokémon encyclopedia.
Kirikiri Mountain (Japanese: キリキリ山 Mt. Kirikiri) is an anime-exclusion location in Hoenn, found somewhere between Littleroot Town and Fortree City. It was featured in Me, Myself and Time. The mountain is well known for its thick fog, which often leaves travelers disoriented.
Places of Interest
Baltoy civilization ruins
The wall from the Baltoy civilization
The Baltoy civilization ruins are a hidden location found within Kirikiri Mountain, only accessible via tree hollow. Entering the cave, there are glyphs on the wall from an ancient Baltoy civilization, as well as an ancient structure that, through a Baltoy's Rapid Spin, allows a person and Pokémon to time travel.
After being separated from his friends, Ash encountered Calista, an amateur archaeologist who hoped to find the Baltoy civilization after receiving a peculiar phone call. Together, they met a mysterious woman who guided them to the ruins, revealing some of the civilization's secrets, including the time travel device. The mysterious woman later identified herself as an adult Calista before returning back to her own time.