Really fascinating essay by Robert Bast.
Will make you think about the entire scope of human history. The ancient Vedantic writings have a chain of ownership that assures some consistency going back around 12,000 years. There's an element of truth in here somewhere that is vindicated by identical accounts found on the other side of the planet with completely different races of people.
I was aware of this thread running through ancient writings when I first started to think about building my own shelter back in 1997. The Avesta describing a terrible poisonous snow aboveground that would kill all living things not deep in the "ark" beneath the ground. The ancients mentioned "the burning sky" and the "black ashfall" again and again in the dreams of Gilgamesh.
Look at the colossal underground cities in Turkey and around the Fertile Crescent. Somebody engaged in a huge engineering project to create these places. Unbelievable in scope and logistics.
Note "Ark" can also be translated as "Sanctuary" in Hebrew.