This whole conversation reminds me about the claims of an ancient civilization around the world that pre-existed Sumeria, which is where Noah's sons went after the legendary flood. Sumeria is usually considered one of the oldest, if not the oldest significant civilization, and its beginning is dated to 4500 BC.
This is interesting, because major ruins around the world, whose impressive, megalith-style architecture is seriously debated, appear much older. Gobekli Tepe in Turkey uses the Megaliths in a stonehenge style and its beginning is dated to maybe 10000 BC.
Around lake Titicaca in Peru we find ruins that are aligned to the winter solstice, but are actually slightly misaligned- their directions would have been aligned to where the earth was arranged thousands of years before Sumeria.
The pyramid at Giza is of course a frequently discussed mystery, especially its age. One author writes:
Since precession causes the height of stars to change with time over a period of 26,000 years, try tilting the sky-image anti-clockwise back to the night sky we would observe in the 10,500 BC epoch. We then observe a perfect match of sky-ground image! While star Mintaka, smallest of the 3 stars of Orion's belt is slightly slanted in a south-westerly direction relative to the axis of the Milky Way, the 3rd pyramid too intimates this layout by being offset from the 2 greater pyramids in a similar direction.
There are of course many things curious about the pyramid, but one particularly so is that unlike many other Pharaoh tombs, it does not have any artwork inside. So it is a question for me whether it was simply meant as a normal tomb.
Stonehenge is another mystery considering its massive construction, but another interesting thing is that there are huge megalithic rocks, often arranged artificially, across Europe, along with other times that Stonehenge-style formations were created with smaller stones. On the other hand, Stonehenge is typically dated to 3000-2000 BC, which is well after Sumeria began, although the site itself dates to at least 8000 BC when there were wooden posts put in.
Turning to Russia and the Caucuses, there is a strange phenomena of "Dolmens." They are littered across the northeast edge of the Black Sea. The curious thing about them is we do not know what they were made for. They appear to have acoustic properties. They are made to be surrounded on all sides by either ground, stones, or some kind of concrete, with an empty space inside and a round hole in one of the walls that is plugged up with a round stone. They are also dated to a time before Sumeria, ranging from 25000 BC to 4000 BC.
Here is a map:
Here you can see a stonehenge-type П symbol engraved in the front:
It would be interesting to find out more what is the true story about these things. We do know also that ancient flood-type stories are shared by many cultures around the world.
On the other hand, mainstream archeology in academia seems to strongly dismiss theories about there being major civilizations predating Sumeria, because we do not really have written records from before then.
What we do have are massive structures in places like Puma Punku near lake Titicaca, and Giza, and puzzles about how they were made, what happened to the technology, their date, and how far had their civilization advanced besides just making the structures. It is surprising that they accomplished so much if their literature was at such a low level and they did not even have wheels yet. Perhaps it is just wistful thinking, but in any case it would be interesting to know more about them.