Infamous movie made by director Pier Paulo Pasolini in the mid 70s. It is about a group of middle aged men who have a bunch of kids captive in a castle-like place somewhere in Italy in the 40s. These men force the kids to eat shit, abuse them sexually and physically, and at the end of the movie, torture and mutilate them. The "white ring" DVD of this movie sells for as much as $900.00 on eBay.
When I saw "Salo: The 120 Days of Sodom" at a theater in 1979, by the end of the movie, only a few people were still in the place. Most could not stomach it, and walked out at some point during the film.