Irwin Allen puts a saddle on the Conan Doyle novel and digs in the spurs in this silly adaptation of the eponymous book. Loaded with action but not much else, and well stocked with useless characters such as Frosty the poodle. SEE! Jill St.John, who starts off feisty but ends up as simpering baggage, explore the Amazon in pink tights. HEAR!! Michael Rennie murder the Spanish language. FEEL!!! The sense of loss as Fernando Lamas deadpans the line: "My helicopter". In an interview years later, David Hedison admitted that he HATED this movie, and it's easy to see why. With typical pre-release hype, Irwin Allen teased the public with promises of unbelievably authentic-looking monsters("like nothing you've ever seen before!"). Wrong: they were exactly like everything we've seen before. The actors, from Claude Rains to Fernando Lamas, are all good to very good, but not in this clunker. Their combined talents were wasted, as will be your money if you buy or rent this film. Get it ONLY if you feel compelled to complete a collection of '50s and '60s B-movies, otherwise: don't walk, run!