I really love this beautiful 1970 documentary about a trek through the Western Amazon forest, encountering numerous indigenous tribes but never the Kreen-Akrore people, who manage to elude the top-notch cameras and crew.
The Kreen-Akrore are a forest Indian tribe living in the Amazon basin of Brazil who successfully managed to evade the cameras and crew accompanying the Villas Boas brothers during their attempt to make first contact with these hostile and entirely unknown people.
