The more I read, the more I think that we’ve had civilizations, at least off-and-on, for several hundred thousand if not millions of years. Nothing else makes sense. One example: Mohenjo Daro.
(four months later) Mohenjo Daro is just a bit older than the Great Pyramid, and younger than the prehistoric temples on Malta; but an example of much earlier sites include the Gobekli Tepe site in Anatolia (11K old, 6K older than Stonehenge). I wholeheartedly agree that there’s probably been multiple rises and falls, and the falls were not due to “overspecialization” or other mundane gradualist nonsense.
http://www.smithsonianmag.com/ist/?next=/history/gobekli-tepe-the-worlds-first-temple-83613665/
http://whc.unesco.org/en/list/132