I see this show all the time and love it. The mysteries are intriguing. However, much evidence, particularly the maps showing the world as it was in the last ice age (with Antarctica properly mapped), make me believe the is a lost HUMAN civilization that had great technology. Perhaps the great catacyclsm/flood decimated this previous civilization. Most of the world is water, and the land remains would be so buried that it wouldn't be implausible to think all we'd find left of that advanced global civilization is a few artifacts. So, perhaps mankind, or an earlier rendition of mankind, is responsible for the LARGE NUMBER of technological contradictions with our current historical record.
This is just a wild theory, but I wanted to throw it out there... as it *seems* more plausible than aliens, *since* we have yet to detect anything at SETI, suggesting advanced societies probably destroy themselves, or are otherwise destroyed and typically exist only for a brief second in the eternity of time.
So, if human civilization has been created and wiped out a few times over, when is it due to happen again? Who knows. We can't know, with certainty. Much like a Noah's Ark though, I hope there are contingencies to plan for the survival of our current species (there are of plants for sure). Perhaps a few people make it through the cataclysm, and help speed the advancement of the next civilization. However, their knowledge is quickly lost through the ages.
And that Crystal Skull ... I mean, that one is truly remarkable, not to mention the Pyramids and such. Well, so much is unexplained. I think we can all agree something is missing from the historical record. Something.
Since religions tends to live the 'longest' as far as historical records go, the common stories in the world's oldest religions can perhaps give us a clue.