12 Monkeys (1995)

Ok, this is very dated in terms of special effects and the story line is a bit clunky as well, so while it doesn't hold up to the test of time, there is some good work in here by then much younger actors.
This is a story of a post apocalyptic future where the future goes back to the past to try to stop it all from happening.  Terry Gilliam is the director and the work that he creates here is very much like his movie Brasil.   In this world, everything is rusty, subterranean, and leaks. The movie uses its future world as a home base and launching pad for the central story, which is set in 1990 and 1996, and is about a time traveler trying to save the world from a deadly plague.  Bruce Willis is the confused emissary from the future, and one of his allies is a mentally unstable son of a researcher played by Brad Pitt.  Now I see where the Coen brothers got the idea to cast him as a gum chewing fitness ditz in Burn After Reading.  He is perfect as an off the rails crazy person here.  The story unfolds somewhat predictably as seen from the present, although at the time it may have seemed more prescient.  Recommended.