Indeed, with a little persistence and some capital this could turn into an interesting project. Like Bir Tawil, it's a piece of land which is not just unclaimed, but in fact definitively disclaimed by the adjacent nations - but instead of being a barren patch of North African desert miles from nowhere, it's a pretty little patch of forestland on a major river in central Europe. Nor does it seem likely that Serbia and Croatia will be settling their differences over the border any time soon.