As far as prison films go, few are as emotionally wrenching as 'The Shawshank Redemption,' which is celebrating its 20th anniversary this September. Adapted from a Stephen King novella, the film tells the story of newly imprisoned Andy (Tim Robbins) and the friendship he strikes up with fellow inmate Red (Morgan Freeman) starting in the late 1940s. Equal parts funny and heartbreaking, the movie debuted in 1994 with a solid thud at the box office only to gain a cult, and then mass, following via home video in the years to come. Now it’s celebrated as one of the greatest films of the 1990s. Here are 13 things you didn’t know about it.