http://nuclearchange.i2p/catalog.html?add=&amp%3Bamp%3Bamp%3Binclude_default=true&amp%3Bamp%3Bamp%3Brem=&amp%3Bamp%3Bamp%3Bpage=2&amp%3Bpage=1
Which by itself is twice as long as recorded history, but then the first evidence of tool use was 3.3million years ago, and our near ancestors were almost as smart as we are.
Complex society basically, is very old, in my opinion, certainly I think there are huge cultures, cvilisations etc, that have been lost to the grind of history.