The Mysterious

Moon over the Bosnian Pyramid of the Sun

There are so many mysteries in the Visoko valley. Four huge pyramids and one long crescent-shaped artificially created mountain, the Temple of Mother Earth, bring us to this question: why? And for that matter, who?

But the monumental above-ground structures are not all.

One of many passageways in Ravne Tunnel Labyrinth.

We don't know who built Ravne, the extensive tunnel labyrinth beneath the pyramids that meanders for hundreds, perhaps thousands, of kilometers beneath the ground surface, a labyrinth that may connect with passages inside the pyramids themselves. We don't know who built Ravne, and we don't know why such an incredible geo-engineering feat was undertaken.

Volunteer János removing "fill-in material" from Ravne tunnel labyrinth.

But most mysterious of all is that we don't know why the Ravne tunnel labyrinth was later filled in with sand and river stones -- filled to the brim, leaving only the underground water channels open but still sealed from view for thousands of years until modern excavation could bring them to (artificial) light.

Underground water channel. The water is still drinkable after thousands of years.

Who filled the tunnel in with sand and river stones? Was it the culture that built the tunnel or a subsequent culture? Who spend decades moving millions of tons of material to fill in a beautifully (and presumably purposefully) constructed tunnel system? Was this culture trying to hide something in the tunnel? Or -- more likely, to my mind -- were they using the material to protect the water channels? What is the water channels' purpose?

Dry-stack wall thousands of years old next to water channel in Ravne tunnel labyrinth.

How did they create vertical "dry-stack" (mortar-free) walls standing several meters high that lasted thousands of years without one stone out of place?

So many mysteries. Thank goodness.

UPDATE:
March 31, 2012

Discoverer of the Bosnian Pyramid complex Semir Osmanagich gives us the latest information on Ravne tunnel labyrinth.