Pheasant Island on the river Bidassoa that runs between France and Spain; administration of the island switches every six months. It has since 1659 when Louis xiv and Philip iv signed the peace Treaty of the Pyrenees on the island. It is a different situation IMO for it has clear and settled ownership, that being both. Accessed by boat,and on it some trees and grass; it has little intrinsic value to either sovereign or local population. It is seen as the place were towns share the duty of cutting the grass. It's not a tourist spot of any sort.