The subterranean approach towards the Bosnian Pyramid of the Sun continues in Summer 2018 through the nearby Ravne tunnel network. Excavations at Ravne began in 2006 when Dr Sam Osmanagić excavated a small cave he suspected was associated with the ancient pyramid complex, located 2.5 km away. Excavations at the site have since revealed over 1 km of passageways that were previously unknown to history, which had later been purposely blocked up with loose gravels. Archaeological features along the passageways include water channels, chambers and over 50 stone drywall structures. Several large megaliths, each weighing at least several tons have also been uncovered within the tunnels. Their form and the material they are composed of is not like anything else found within the surrounding geology.
