Trivia: While Steve McQueen performed most of his own stunts, the only stunt he didn't perform was the 60 foot jump over the Austrian-Swiss border fence. The jump was performed by stuntman Bud Ekins, who later doubled for McQueen in "Bullitt."
Trivia: The attempt to make the locations look wild and uninhabited were obviously not altogether successful. Near the beginning of the movie, some boys are sitting in a sandy clearing in public-school blazers. On the right of the screen you can clearly see a tent peg with ANTONY M written on it. Also, as one of Jack's choirboy-hunters thrashes through the undergrowth, look closely and you can see that he accidentally impales an old beer can.
Trivia: The chapel that was built for the movie had to be torn down immediately after filming, as it was on rented property.
Trivia: The film was to have run six hours with two intermissions, but it was cut down to four with one.
Trivia: The Chinese extras cast in this film were almost all Spanish residents, especially in Madrid. This was done to such an extreme extent that some Chinese restaurants and other Chinese-Spanish-owned businesses in the Madrid area especially were forced to close for a few days due to lack of personnel.
Trivia: Patricia Neal won the Academy Award for Best Actress for her role as Alma Brown, even though she's only on screen for a total of 21 minutes and 51 seconds. This is the shortest performance ever to win the Award.
Trivia: Sorrell Booke plays Alan Alda's father in the movie, even though in real life he's only six years older than Alda.
Trivia: Lionel Jeffries was only 5 years older than June Thorburn, who plays his daughter.
Trivia: Fay Compton and Michael Redgrave play mother and son in this film. In real life, Compton was only thirteen years older than Redgrave.