Sir Roger Moore said that he felt miscast in this movie.

This movie's exotic exteriors were locales filmed on the Greek Island of Rhodes.

This movie is one of a handful of action-thriller movies made within a five year time-span around the time of the mid to late 1970s and early 1980s that used a mountaintop monastery in Greece. Other movies include Sky Riders (1976) and For Your Eyes Only (1981).

The title card sets this movie in 1944, but is no more specific than that. During this movie, Major Volkmann (Anthony Valentine) shows other German officers footage of V-2 rocket attacks in London, which didn't occur until September 8th of that year. This means that the story must occur no earlier than late summer of 1944. While it would also appear that the events of the film occurred no later than October 1944, given that British forces began arriving there at that time, history was more complicated than that. Mainland Greece was "liberated" in the fall of '44, mostly by the German military's evacuation. Some of the Greek islands, on the other hand, remained under Axis control until the end of the war in Europe, including Crete (mentioned briefly by Major Vogel) and Rhodes (where much of the film was shot).

Philip Locke was dubbed by Michael Sheard.

To initially establish Sir Roger Moore's German character as being unaligned with the S.S., when the Nazi officers give him the Heil Hitler stiffed-armed salute, Moore returns it with a regular military salute.

The movie is notable for featuring distinctive Greek architecture. Examples include a Greek mosque, Ottoman Turkish buildings, and a mountaintop monastery.

The action largely takes place in Stalag Luft VII Z, "somewhere in the Greek Islands 1944" (named in dialogue as Kariai). The monastery is found on Mount Athena.

To evoke the Greek theme and setting, on American movie posters, instead of using the letter "e/E", the Greek alphabet's uppercase sigma symbol was used for that letter in the wording of the title.

David Niven and Claudia Cardinale appeared in The Pink Panther (1963). Niven and William Holden appeared in Otto Preminger's The Moon is Blue (1953).

Second of four movies in which David Niven and Sir Roger Moore appeared. The others being The King's Thief (1955), The Sea Wolves (1980), and Curse of the Pink Panther (1983).

Michael Sheard states in his memoirs, he believes he was only cast because they were unable to get a star name to play Sergeant Mann.

Sir Roger Moore was famous for playing James Bond when this movie was made. This movie was released between The Spy Who Loved Me (1977) and Moonraker (1979).

Takes place one week before the Invasion of Mainland Greece which occurred in October 1944. Confirmed by Telly Savalas who dr does a message saying the invasion will take place 'one week from today'.

The opening scene show the Tsambika Monastery perched on a hill about 300 meters high with stunning views over the area of Kolymbia to the north. The second monastery on the side of a mountain is the Simonopetra Monastery, also Monastery of Simonos Petra, is an Eastern Orthodox monastery in the monastic state of Mount Athos in Greece. Simonopetra ranks thirteenth in the hierarchy of the Athonite monasteries. The monastery is located in the southern coast of the Athos peninsula, between the Athonite port of Dafni and Osiou Grigoriou monastery.

This was the only movie in which Telly Savalas and Sir Roger Moore appeared. They were famous for being part of the James Bond film franchise. Savalas played Ernst Stavro Blofeld in On Her Majesty's Secret Service (1969), while Moore played James Bond in seven movies. David Niven, also appearing in this movie, played James Bond in Casino Royale (1967).

Sir Roger Moore vocally plays against type, and has a German accent in this movie.

Final theatrical movie of Paul Stassino (Zeno's Man).

Elliott Gould and Telly Savalas appeared in Capricorn One (1977).

David Niven (Professor Blake) was the father of producer David Niven, Jr.

Paul Michael Glaser was originally announced as part of the cast.

Elliott Gould and Sir Roger Moore appeared in The Naked Face (1984).

O.J. Simpson was offered the role of Judson.

The music used over the establishing shot of the Stalag leading to Roger Moore's entrance starts as a grim military march but quickly morphs into a lighthearted dixieland rendition of "When the Saints go Marching In" which finishes right as Moore's character walks to the camp entrance. Ten years earlier Moore starred in the TV series "The Saint" as the title character of Simon Templar.

Joss Ackland was offered the role of Sergeant Mann.

Peter Vaughn was offered the role of Sergeant Mann.

None of the big stars or other actors and actresses are actually credited on-screen with their character names, except for "and Elliott Gould as Charlie".

Closing credits: The characters and incidents portrayed and the names used herein are fictitious, and any similarity to the name, character or history of any person is entirely coincidental and unintentional.

Both Sir Roger Moore and Elliot Gould are seen in this movie smoking cigars. In real life, both actors were cigar smokers, Sir Roger Moore having died of cancer due to smoking.

William Holden: As a cigar-smoking prisoner of war. Elliott Gould walks by Holden and asks him, "Are you still here?" This P.O.W. bit was an in-joke reference to Holden's starring role in Stalag 17 (1953). Holden was in a relationship at the time with Stefanie Powers, who appeared in this movie.