I have always been intrigued by the rate of technological development. Ten thousand years ago, our species lived in caves and hunted and gathered our food. Since that time we have developed agriculture, domesticated not only animals but almost all of nature and are now on the verge of reaching for the stars; all this in ten thousand years. Our species however, is almost seven times that old.
For the first seventy or so thousand years did humanity everywhere just take it easy in our caves? Was the preponderance of predatory species in the world just so great that we, as a species dare not go far from the safety of our holes in the ground? Or have we perhaps risen to great technological heights many times during these lost eons only to fall back to the depths of barbarism?
Take a look at the pyramids that were found in Bosnia. They are so ancient that the people who lived in the region had long forgotten about them and the people who dwelled there. Dirt had covered them for multiple thousands of years and everyone just thought they were mountains, until someone dug into them. They discovered that many pyramids covered the area and that tunnels bellow the valley that was created between them still remained. All of it determined to be older than any written language, possibly being built during the last ice age.
This world is immense, only the surface has been explored and our species has been around for a really long time. Who knows what the true ancient history of our world is. It seems the more we discover the less we know.
Just a thought.