12 Angry Men is the grand-daddy of the court-room drama sub-genre.

There have been some great court-room drama movies. (The Verdict, with Paul Newman, is my personal favourite. Director Sidney Lumet, for whom 12 Angry Men was his first feature film, also went on to direct this many years later, so clearly he felt an affinity for the genre).  

Lumet’s 1957 movie sets the template: a claustrophobic focus primarily around a single set (usually the courtroom, but in this case the juror’s room); a twisty open-and-shut case that turns out to be not so open-and-shut; and a tense confrontation or cross-examination during which one party breaks down and spills the beans. 

In 12 Angry Men, Henry Fonda is the one initially dissenting juror (“number 8”), who over the course of the movie persuades the other 11 jurors that there is enough reasonable doubt from them to change their verdict from guilty to not guilty in a murder case.  Lee J Cobb is his primary antagonist as a loud-mouthed and belligerent fellow juror, who breaks down in the end.

This is a Belgian poster, which I sold awhile back.