An intriguing hypothesis suggests the existence of an advanced civilization 12,000 years ago, who potentially lived on a continent now submerged due to cataclysmic flooding (detailed in the Altai Flood theory on Wikipedia). This speculative and unverified theory suggests that the survivors of this civilization dispersed globally, and influenced monumental architectural works, like the Pyramids or Göbekli Tepe, as a mean to saveguard their knowledge. There is an english website (https://builders-of-the-ancient-mysteries.com/about-bam/) and a french book and movie. This is a lot of speculation, but it is interesting to consider in the light of this article.