25 Most Important Movies of All Time, Ranked by MovieWeb

"What makes a film important? While an important movie doesn't necessarily need to comply with all of these rules, nailing several of them helps assure a film's lasting importance. It has to be more than mere entertainment. It has to: innovate or influence the craft itself in technical and artistic ways; capture or reflect a cultural or historical moment; open your mind or imagination to new ideas or ways of seeing the world. Its same effect wouldn't exist if it was a book or a play. Of course, while recent movies can be important to the medium, it's much more likely for older films to take the mantle. After all, they did it first. While later pictures may be more entertaining or aesthetically pleasing, there's a discernible difference between 'the best' and 'the most important.' As such, these aren't exactly popcorn flicks, and that's totally okay; movies don't have to be important. No, these are films for filmmakers, cinema for cinephiles." - movieweb.com