It might be even bigger than the biggest stone sphere in Costa Rica.
I think this one is a natural concretion sphere, because of the iron content and the presence of layered shells, clearly visible in the picture.
Archeologist tell us that some primitive tribes cut huge blocks of stones, right angled, surfaces flat and weighing tons, to construct their buildings, without considering they didn't have the tools to move or lift them.
The stones have been cut so precisely that you cannot get a credit card in between.
This was done, because this method of construction protects the building from collapse in the case of an earthquake.
Also notice that when the side of the stones are angled, the sides of both stones still fit perfectly together. Jock Doubleday has examined the river Fojnica that runs through the valley of the Bosnian pyramids, and found that all along the river sides there was many remains of artificially created and placed clay blocks and plates that points to the shaping of the river by the ancients.
A lot of spheres have been covered by dirt for thousands of years and are usually discovered by accident.It doesn't take much to see that the walls at Daorson were already there when the Illyrian tribes moved in.These constructions, now shown to also be in Europe, were once built by an advanced worldwide civilization.Thus people have been looking around and, yes, they found other evidence.Large stone spheres have been found in Costa Rica and Middle America, associated with ancient cultures who were able to shape perfect spheres out of different rock, some of them very large. To archeologist they are just an artwork, but those who work with energy know that they are placed (if still in original position) on earth energy spots, and thus have a function in energy transformation or distribution.
The Bosnian Pyramids by themselves show that they are the constructs of a very well developed society.