During the swimming scene at the pool, Hesh-Ke was supposed to be topless with a loincloth. In an interview, Julie Newmar stated that at the last minute she decided to do the scene fully nude and no one, especially the actors and crew, argued with her about the decision.
The pool and waterfall where part of the action takes place was man-made and the water had to be hauled in by tanker truck.
Filming for this movie prevented Julie Newmar from appearing as Catwoman in the third season of Batman (1966); she was replaced by Eartha Kitt.
The film is based on the novel of the same name by Heck Allen using the pen name Will Henry, telling the story of how the lure of gold corrupts a diverse group of people. The novel was loosely based on the legend of the Lost Adams Diggings, crediting the J. Frank Dobie account of the legend (Apache Gold and Yaqui Silver) in the author's notes.
J. Lee Thompson: [cast] This film reunites the director with Gregory Peck and Sir Anthony Quayle, who all had worked together on The Guns of Navarone (1961). Peck and Telly Savalas were also in Thompson's Cape Fear (1962).