Tarzan, Mystery Of The Jungle (1973)

aka's: Green Inferno/Tarzán Y El Misterio De La Selva/Tarzan And The Jungle Mystery

A group of student activists travel from New York City to the Amazon to save the rain forest. However, once they arrive, they soon discover that they are not alone – with dire consequences. Stars José Luis Ayestarán, Didi Sherman and César Burner.

The picture quality for this film is a bit soft, but currently the best English language version available anywhere.