Dr. Sam Osmanagich, Ph.D. and Lead Excavator Edo Građan explore a newly discovered open tunnel in Ravne Tunnel Labyrinth on July 6, 2017. Most new tunnels in Ravne Tunnel Labyrinth were filled in to the brim with “fill-in material” (loose sand and small river stones) an estimated 4,600 years ago by an unknown advanced cultures. The tunnel discovered and explored on July 6, 2017 was not filled but is open, traveling north-south.






