|This article is about a/an creation source in Kamen Rider W.|
The Gaia Memory (地球の記憶, Chikyū no Kioku, literally "Earth Memory") also called the True Gaia Memory (真のガイアメモリ, Shin no Gaia Memori) is a plot element in Kamen Rider W, as well as Earth's consciousness.
It was discovered below the Sonozaki Estate by Ryubee Sonozaki. After finding it Ryubee brought his family to see it, but his son, Raito Sonozaki died when falling into the "fountain," but he was then resurrected as the Gaia Memory's avatar. Knowing this gave Raito access to the planet's infinite knowledge, Ryubee began his plans for the Gaia Impact.
Through his son, Ryubee founded the Museum and had scientists create the Gaia Memories to be used to create Dopants. Ryubee's wife, Fumine Sonozaki (Shroud) also created the refined Gaia Memories to be used by Kamen Riders.
When the Gaia Memory started the Gaia Impact, and after it was ruined thanks to the Kamen Riders, the Sonozaki Estate collapsed, burying the Gaia Memory's fountain, preventing any new Gaia Memories to be made for distribution.
Presumably the Underworld in Kamen Rider × Kamen Rider Wizard & Fourze: Movie War Ultimatum is located somewhere in the subconscious of the True Gaia Memory.