History of Religion

Ali just posted this neat 90-second animation of the history of religion:

How has the geography of religion evolved over the centuries, and where has it sparked wars? Our map gives us a brief history of the world's most well-known religions: Christianity, Islam, Hinduism, Buddhism, and Judaism. Selected periods of inter-religious bloodshed are also highlighted. Want to see 5,000 years of religion in 90 seconds? Ready, Set, Go!

Ali writes:

This is of course, simply a map of the beliefs of the rulers in a given area, but it's a pretty good illustration nonetheless.

Why does watching this remind me of a game of "Risk"?

Update: See a much larger version here.