Well, that would certainly explain how they knew that the tunnels had been "under water" several times. Yes, indeed.

Someone asked me (on another board) about the sea that had been in that region. I looked it up (there's not much in English, but I'm sure there's a wealth of it in Czec and other languages I can't read) and there was indeed a small branch of the ocean there that dried up. I can't recall the exact dates, but memory says it was much longer ago than 12,000 years. I was trying to relate it to Death Valley, which did dry up fairly recently and commented that if it was only 12,000 years ago the saline in the soil would have quite an impact on the water quality and plant life.

That also explains the mysterious iron rings the person was asking me about (he or she is from Bosnia, I believe).

Only seen by one person, eh? And never photographed or brought in for proof? Can you say "The Emerald Tablets of Thoth", boys and girls? I thought you could.