for example the egyptians. i think they had advanced technologies. then once the civilization died off for whatever reasons ( maybe an earthquake, flood, meteor etc), millions of years later all their machines and writings disintegrated. the only tangible things that remained through the elements are of course things made out of stone, like pyramids and sculptures. NOW CHECK THIS OUT. down the line when our civilization is dead and gone, after a while a new civilization will start to grow and eventually start digging things up trying to learn about "their primitive ancestors" (which is us). they will find things like the statue of liberty and ask themselves " how did they build this with no tools, they were so primitive?" see where i'm coming from? therefore i believe there were past civilizations like egyptians, mayans, romans etc but not primitave
and i'm not talking about cavemen i'm talking about civilizations from way way back
and i'm not talking about cavemen i'm talking about civilizations from way way back