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https://www.bighistoryproject.com/chapters/1

Here you go: http://www.thegreatcourses.com/courses/big-history-the-big-b...

The audio edition is cheaper through audible.com :

http://www.amazon.com/Big-History-Bang-Earth-Humanity/dp/B00...

Also available on the iTunes store

I took David Christian's unit last semester at university and had him as a tutor, it was probably one of the most interesting and thought provoking units I've taken! Feel free to ask any questions!