From Bulbapedia, the community-driven Pokémon encyclopedia.
Sunyshore Tower (Japanese: ナギサタワー Nagisa Tower) is an anime-exclusive building located in Sunyshore City. The Tower provides the required energy for the various technological machines in Sunyshore City.
In Flint Sparks the Fire!, Ash and his friends, along with Flint, found Volkner inside the tower. Ash asked Volkner to a Gym battle, but was refused.
In The Fleeing Tower of Sunyshore!, Team Rocket stole the tower and turned it into a rocket ship in order to take it to Team Rocket Headquarters. However, they were defeated by Ash and his newly evolved Torterra. Volkner returned the tower to its original place, but since it was heavily damaged, he put off the Gym battle with Ash so he could repair it.
Team Rocket once again tried to infiltrate the Tower in The Eighth Wonder of the Sinnoh World!, but Volkner had improved the security in the Tower, which made it impossible to take control like they did before. However, they managed to short-circuit the power supply to the Sunyshore Gym, shutting out the power while Ash and Volkner had their Gym battle.
- The Sunyshore Tower is similar to the Vista Lighthouse. Volkner can be found in the Vista Lighthouse in the games, refusing to accept Gym opponents, as in this episode of the anime.
- The Sunyshore Tower resembles the "Tower of the Sun", the symbol of Expo '70 held in Osaka, Japan.