A throne from the manga and anime One Piece; it serves as a symbol that the world of One Piece has not one ruler, but is governed as a federation of 170 nations.
Warning, heavy spoilers follow here!
The throne isn't actually empty, in reality, Imu sits on it in secret, making him the ruler of the world above even the Five Elders, whom he granted immortality and other powers (something he can take away at any time).
