The speaking voices of almost all of the European actresses in this movie were dubbed by Annie Ross of the famous jazz vocalese group Lambert Hendricks & Ross.
Raquel Welch broke her wrist while training for Kansas City Bomber (1972). Production shut down for six weeks, during which time, she flew to Budapest and filmed her cameo in this movie. Said Welch of the eager producers: "They didn't care if my arm was broken." The costume department came up with ways to conceal her wrist.
Writer and director Edward Dmytryk said in his biography that couple Richard Burton and Dame Elizabeth Taylor had serious alcohol problems during shooting. They were rarely sober.
Richard Burton once said about this movie that he was deliberately trying to imitate seasoned horror genre actor Vincent Price.