Why Do Screws Have Different Heads?

Inside History on Instagram: "You’re witnessing a world few were ever meant to see! For the first time — with the help of the BBC — you’re watching real footage of an uncontacted tribe, deep in the heart of the Amazon rainforest. These people have never used a phone, never seen a city, and don’t speak any language you know. They live entirely off the land, following ancient traditions that have endured for thousands of years. Filmed from a kilometer above, through a powerful zoom lens, this dist