The last 13,000 years of history explained

At the end of the last ice age, 11,000 BC, humans all over the globe were at the same stage of development: stone age hunter/gatherers. By 1500 AD, huge disparities in development occurred: some civilizations were iron age, some bronze age, and some humans elsewhere remained stone age hunter/gatherers. Dr. Jared Diamond, a professor of geography and of environmental health sciences at UCLA, thinks he can explain why humans developed at different rates in different places on the Earth. Principally, he believes that the development of human civilization required domesticatable plants and animals. For reasons of geography, he says, this favored the Eurasian land mass. His speech is a good read if you are interested in the big picture of history.