Actually, humanity has arguably known anarchism all over the world for tens of thousands of years - most of its existence. Historians label that period in time prehistory.
That's a good point. The first 90k years of humanity were exclusively free of any authority greater than the tribe. (as far as we know)
That era included some of humanities greatest challenges; such as the ice ages, competition with Neanderthals, and legendary adventures with Pleistocene beasts. I doubt we have ever been in more danger, or more free.