Man from Deep River

The film that started the Italian cannibal cycle, by remaking A Man Called Horse in Thailand. A Western photographer is captured by a tribe, endures ritual ordeals, assimilates, and comes to love the people who took him, before the film's more lurid final act. It is more anthropological travelogue than gore piece for much of its length.

Umberto Lenzi bolts the mondo apparatus onto the story, real rituals, real animal slaughter, documentary inserts, and sets the template the cycle would follow. It sat mostly unnoticed for five years before the boom it started.

Historically the origin point, and tamer than what it spawned, though the animal footage is real.