Consider that the greatest ancient civilizations degraded all at the same time, Old Kingdom Egypt, the Indus Valley Civilization, ancient Sumer, and the portion of the great bronze age civilization (Atlantis) east of the Sierra Nevada mountains of extreme southern Spain which turned from verdant to desert, as did those other civilizations, because in reality that was when the Ice Age ended, with submerged ruins offshore further proving it, having ended during about a century beginning circa 1500 b. c. when the world ocean had cooled to today’s temperatures about 900 years after Noah’s Flood.