If we knew that the Nile was lush, green and wet ~11,000 or 9,000 years ago... that maps to a way more wet level not "thousands of years of rain" as was stated

If we knew that the Nile was lush, green and wet ~11,000 or 9,000 years ago... that maps to a way more wet level not "thousands of years of rain" as was stated in a few Docs - but maybe a tidal lapping... If a planet were to be inundated on a regular schedule by comets, or asteroids which caused tsunamis as your primary inundation-threat -- the best architectural style are the angles of all pyramidal structures the structures of the irregular machu picchu blocks, werent for earthquakes (only) -- perhaps they were for deluges. Massive tsunamis - but they failed because it was crops that failed - not their walls... Their math survives for us.