Vieille Montagne was a zinc mine in Kelmis, a town in Belgium between Liège and Aachen. The mine's name is French for "old mountain" or "old mine", and this is also reflected in its German name, Altenberg. The mine was once a bone of contention between Prussia on the one side and the United Kingdom of the Netherlands on the other, that resulted in a piece of land that became the territory of Neutral Moresnet.