Native Intelligence (2005)

I recommend the following video by CGP Grey, largely based on the book "Guns, Germs and Steel" by Jared Diamond: https://www.youtube.com/watch?v=JEYh5WACqEk

Now, history doesn't give a lot of merit to natives. The largest battle in the Americas, the siege of the Aztec capital Tenochtitlan, was won with the help of 80,000 to 200,000 Tlaxcalan natives, which amounted for 99% of the infantry used.

I highly recommend his two books, 1491 and 1493. (see the bottom of the article) Truly fascinating reading.