As we all know too well, when two countries fall out, things can deteriorate very quickly indeed. Except perhaps when it comes to Denmark and Canada. Engaged in a territorial dispute for years over Hans Island (a 1.3km² rock in the Arctic), the two countries warn each other before they visit and, as a little snub, leave a bottle of Danish schnapps or Canadian whiskey behind. And if you feel like it, you can decide the little island belongs to you, too! The Hans Universalis website lets anyone become a virtual resident of Hans Island simply by filling out a Declaration of Entitlement, which is a way of getting the UN to confirm it sees Hans Island as belonging to nobody in particular (Terra Nullius).