GURPS - Aztecs

From their website:

"Blood And Sacrifice!

The empire of the Aztecs stretched from ocean to ocean. They worshipped hundreds of gods, kept elaborate calendars and built gigantic stone pyramids that still stand as testament to their might. Their relentless armies seemed unstoppable.

Then, in 1519, a few hundred Spanish invaders toppled it all.

To the Spanish, the Aztecs were monstrous savages . . . pagans who tore the living hearts from thousands of innocent victims to feed a bloody idol. They never understood the culture they were destroying . . . or the philosophy behind the cruelty. The Aztec society was totally alien, stranger than any fantasy land. Now you can visit the world of the Aztecs from the inside."