“An Occurrence at Owl Creek” is a 1962 French short film (La rivière du hibou, directed by Robert Enrico and produced by Marcel Ichac and Paul de Roubaix) that was based on a story by Ambrose Gwinett Bierce, aka “Bitter Bierce.” The story was originally published by the The San Francisco Examiner in 1890, and was first included in Bierce’s 1891 book Tales of Soldiers and Civilians. The story, set during the Civil War (during the war, Bierce served as a First Lieutenant, in the Union), is about the execution of a spy by hanging. Very creepy atmosphere—love it!
I recommend watching the 28-minute short before reading the wiki link, since it gives away the ending.
This episode was incorporated into the Twilight Zone compendium, in Season 5, episode 22, on Feb 28, 1964, apparently, from what I can find, as-is. Well, with the addition of Rod Serling doing his usual monologue. According to Wikipedia, “…this episode’s introduction is notable for Rod Serling breaking the fourth wall even more than usual, as he explains how the film was shot overseas and later picked up to air as part of The Twilight Zone.”
So, enjoy—it’s packed full of cool, creepy, Civil War atmosphere!