If anyone is interested, the Spanish government has just changed the method of calculating land areas. Or rather, of describing them; instead of calling a plot 4.0 hectares, or whatever, they will call it 3.9999 (recurring). This is in keeping with standard statistical practice, and apparently of no importance, but it actually has an interesting consequence: given the (perhaps temporary) margin between the physically measured areas and those registered with the "catastro oficial", there will be slivers of land, of non-negligible width, that will legally have no owner.
It will not be easy, but with a well considered buying plan, based on surrounding areas and carefully calculated shapes, it should be possible to accumulate a quantity of land which is yours because it is nobody's. It has the double advantage that it cannot be taxed, since legally it will belong to the crown (by default in allodial title).
I don't have the money to make anything of this, as it would require a very big investment to make something of it, but I offer the suggestion to anyone, with a good lawyer and a good surveyor, who might be able to use it.
Namibia, Nambia, whatever
31 minutes ago