The film is based on a true World War II incident that occurred when the German army was making its last stand in Italy.
A whistling theme vocalized by children in the film also features as a track on Ennio Morricone's musical score for the movie.
Sylva Koscina said of this movie, "It shows how war destroys mentally as well as physically. We are all destroyed . . . myself, Rock [Rock Hudson] and the children."
During World War II Sylva Koscina was a child in Yugoslavia and noted that she became very emotionally involved in this film because she saw so much death and destruction caused by the war there.
Many critics savaged this film upon its release because of what they deemed the uncomfortable example of children killing and being killed in a military operation.