Semir Osmanagic said Visocica Hill, about 18 miles from Sarajevo, is actually a pyramid built by people who were the first inhabitants of the Balkans. The researcher said the hill, which is about 2,300 feet high, is man-made. The hill includes sandstone slabs 17 feet below the surface. Sandstone, he said, is not a naturally occurring rock in the area.

Source: turnto10.com