Gaia Tower

The Gaia Tower was a Museum facility located on an island near Futo City where Philip was kept for the production of Gaia Memories. The area appeared to have been run by Saeko Sonozaki as she is the only member of the Sonozaki family present and there was no one else of high Museum ranks present. When Sokichi Narumi with his protege, Shotaro Hidari infiltrated the facility under a job, Sokichi dies after being shot in the back when being pursued by the tower's guards and in order to fight back, Shotaro and Philip transform into Kamen Rider Double for the first time which in the process destroys some of the tower. In the ensuing fight more of the tower collapses but Shotaro and Philip escape.

In Begin's Night, Shotaro and Philip return to the now destroyed tower after a fight with the Dummy Dopant as Kamen Rider Skull to find answers to the sudden reappearance of Sokichi, confirming his death but was never found as well as the Dummy Dopant's identity.