Jared Diamond's Guns, Germs, and Steel, a history of human civilization over the last 13,000 years, attempts to explain why Eurasian civilizations, as a whole, have survived and conquered others. Diamond argues that the disparities in power and technology do not reflect cultural or racial differences, but rather originate in environmental differences powerfully amplified by various positive feedback loops. He also argues that societies with food surpluses and high-to-moderate degrees of interaction with outsiders are more likely to encourage people to realize their full potential and to adopt new inventions.

This is the 2005 National Geographic documentary based on the book that was aired on PBS.

Parts II & III:

http://video.google.com/videoplay?docid=6846344734969027300

http://video.google.com/videoplay?docid=-3449100874735282191