it freaks me out when I think about this place too much. If the ruins are 15,000 years old, then when did they begin? What was their view of the world they lived in?
Combine this site with "Out Of Place Artifacts", I can't help but think civilization has risen and fallen countless times in the past.
The Chinese have pottery in their museums that date back 12,000 years or so. They have no records of those times.