When it comes to really knowing something, it can be really helpful looking into, even studying the history of how it came to be. Below are two of the most interesting, touching and fascinating pieces of video footage I've seen for a while, they're about tribes in the Amazon who have never had contact with 'civilized' humans. That's where we came from. The documentary by Nat Geo is called First Contact - Lost Tribes of the Amazon and is beautiful watch...
The recommended videos following this one are equally fascinating. Rightly or wrongly, people are coming into contact with these isolated tribes, fascinating, touching and interesting it is none the less... Here is another: