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The monuments of the GC are the pyramid ruins that we see with our eyes. We are not allowed to excavate as is Semir Osmanagic is with the Bosnian pyramid array.
Anyone can study the archaeological sites and digs to find that they are heavily monitored, do not dig, do not disturb nor go beyond certain points and each location deemed spiritual to the natives, off limits, etc. The answer to your question is, if archaeological studies were allowed, will find that the cultures that resided within the pyramid array come after they were built in a postdiluvian time.
My interest is not what is found regarding human civilizations because they are logically and most likely migratory people over the Bering Strait. I'm on a venture to solve the mystery of the era before the great flood which proves the flood occurred, and what this world was before repopulated with modern human beings. The Smithsonian's secret archives most likely house what was excavated at the turn of the century which would include Nephilum skeleton remains.
The destruction caused by the epic flood was enough to destroy them to a dilapidated state of erosion and over time; enough to appear natural with animals and vegetation, however, because the top most peaks align with stars, none of the formations appear to be curvilinear, rather 90 degree angles, and there is no question they are arranged and not sculpted by a thin in comparison river arbitrarily. I'm excited that you asked the question as I'm certain more will follow.
In summary, I'm willing to have the theory debunked.... I was a child who loved what I saw and would like to remain in that condition of natural awe, but if it's artificial, I'd like to confirm that as well as an adult in awe.