Lists of science fiction movies are a common item for discussion on the Ars staff Slack channel—particularly short lists of the best science fiction movies ever made. But "best" is an impossible word to quantify in any broadly applicable way—one person's "best ever" might be another person's worst, especially in a genre of movies as rich and varied as science fiction.
Rather than try to pull together another tired "top ten sci-fi movies" listicle, we've instead polled the Ars staff to try to come up with a definitive "science fiction bucket list"—that is, a list of sci-fi movies that you should absolutely see at least once before you die. They aren't necessarily the "best" movies by any specific set of criteria, but every film on this list is outstanding in some particular way. Some are groundbreaking in their stories or subject matter, some are controversial, and some contain a character or plot twist that became an archetype, referenced in and reused by countless other films.