Devil's Tower

Devil's Tower is Ganzack's tower which was created in Medaka's home town. It was later revealed to be a hidden cannon designed to destroy the rest of the island.

Layout
The tower has a big blue entrance and is surrounded by white walls and pillars with a red gem on top of each one. The tower itself is on top of a black and white structure of some sort. The tower is covered in gold and in the shape of a maned dragon with no arms breathing golden fire.

History
Herring and all the other male villagers were forced to work on constructing the Devil's Tower, without knowing what it was being made for. Later, during Luffy's battle with Ganzack, it was revealed that Devil's Tower was nothing else than a cannon made with the purpose of destroying the whole island except for Ganzack's pirate ship.