I've got no idea about Bosnian geology, but just from the photo, I can see that those are not man-made 'pyramids'.
Any geologist in South Africa would be able to tell you those 'pyramids' are a result of a hard cap (most likely basalt) underlain by softer sedimentary rocks. Erosion does the job. We've literally got millions of those features in the Karoo.
Hey, but he's a 'social scientist' who thinks that he knows more about geology than those hundreds of thousands of geologists from all over the world... wonder if he knows what a basalt is?