Trivia

When the group goes skydiving with the mother, they jump from the same plane that was used in the skydiving film Les parachutistes arrivent (1969). The plane is painted exactly the same and has the exact same registration number on the side (N22418).

The plane in the skydiving scenes is a 1940 Howard DGA-15P, registration N22418. A total of 520 were built from 1939 to 1944. As of 2019 it is still registered with the FAA.

Jeanne Crain turned down the role of Astrid Steele.

Re-released in late 1970 as part of a double feature with Les Passions des vampires (1970), and re-titled "The Cult of the Damned".

First film for Jennifer Jones since Jeunes Gens en colère (1966) and her suicide attempt in 1967.