Richard Hoyle, Bosnian Pyramid of the Sun Foundation Geologist
Introduction
The Ravne conglomerate is a rock unit located on the outskirts of the central Bosnian city of Visoko, 25km northwest of the Bosnian capital, Sarajevo. The conglomerate is confined to a small area near to the flood plain of the River Bosna, the namesake of Bosnia. In 2005, the deposit was identified as a site of geoarchaeological significance when Anthropologist Dr Sam Osmanagich discovered a subterranean network of prehistoric tunnels cutting through the interior of the rock unit. The tunnels, which run for 10’s of kilometres underground, offer a unique opportunity to step inside a rock to observe the interior structure of a geologically recent gravel bed.