Latitutde: 43.976944 Longitude: 18.176111
The hills are located near the town of Visoko, northwest of Sarajevo. The town was Bosnia's capital during the Middle Ages, and ruins of a medieval fortress are located atop Visočica hill. The fortress was built over an old Roman Empire observation post, which in turn was constructed over the ruins of an ancient settlement. The hills themselves, which form striking pyramidal shapes, are a type known as flatirons. Archaeological geologist Paul Heinrich of Louisiana State University has pointed out that these formations are common throughout the world, giving the example of the so-called 'Russian Twin Pyramids' in Vladivostok.
In October 2005, Osmanagić and his supporters initiated a long-running media campaign to promote the pseudo-scientific belief that Visočica hill and the surrounding hills are not flatirons, but an ancient pyramid complex. In an interview with Philip Coppens in Nexus (April–May 2006), Osmanagić suggested that they were most likely constructed by the Illyrians, who (according to Osmanagić) lived in the area from 12,000 BC to 500 BC. He has since argued that the hill is an example of cultures building on top of other cultures. In 2017 he was reported to have claimed that the structures date back 34,000 years.
Tunnels around the hill complex, which have been named Ravne tunnels, are claimed to be an ancient man-made underground network. They are claimed to be 2.4 miles (3.8km) long. It is claimed that within them were found fossilised leaves dating back 34,000 years.