Trivia

Vera Miles had her head shaved for her role in this film, which resulted in having to wear a wig for her role in Psycho (1960). (In fact, except for Barbara Bel Geddes, who wore a wig, all the actresses playing the title characters had their heads shaved.)

The producers planned to shoot the film on location in Yugoslavia but the Yugoslav Communist government refused to cooperate or allow shooting. Most scenes were shot in Italy and Austria instead.

Silvana Mangano replaced Gina Lollobrigida. Officially it was because Lollobrigida didn't want to shave her head but insiders felt she was anxious about the caliber of the other actresses involved.

As a publicity stunt, only women were invited to the film's Rome premiere.

First American-produced film of Jeanne Moreau.