Cannibal Holocaust ( 1980).
This is the controversial and notoroius Italian documentary-esque horror adventure shocker from Ruggero Deoato about these New York documentary filmmakers who are searching in the South American jungles to find lost footage from a filmmaker but finds cannibals.
It's a very morbid, realistic, immoral and fascinating film that assuaults your senses with dark images like cannibalism, impalments, gore, and of course real actual animals getting slaughtered like a large turtle getting it's shell ripped open to be cooked.
Sure it's hard to watch but i highly recommend it to anyone who likes foreign horror and the genre but not for the faint of heart! it's coming on DVD October 25th.