"Time travel hasn't been invented yet. But it will be," Joseph Gordon-Levitt says at the beginning of Looper. That's the thing about time travel: Once you invent a time machine, you just have to use it to travel back to the U.S. Patent Office on the first day it opened, so you can register your invention and serve as inspiration for an endless stream of movies. For decades, Hollywood has been treating the space-time continuum like it's just the daily rushes for editors to cut together.
This summer, for example, X-Men: Days of Future Past sends Hugh Jackman's Wolverine back in time 50 years, while Edge of Tomorrow puts Tom Cruise in a temporal loop, letting him relive the same battle over and over. So crank up your flux capacitor and check out the 20 best time-travel movies ever. By Gavin Edwards