Sci-Fi's Best Time-Travel Tropes, From Fixing the Past to Unreal Time Machines

Time travel is tricky. Not because science hasn't figured out how to make it a real thing, but because anytime it's used as a storytelling device, the plot can be compromised by the type of mind-bending paradoxes that can ruin suspension of disbelief. Rian Johnson's latest film Looper, out Friday, is a time-travel flick that avoids nearly all of that. By focusing on a smart, character-driven story instead of getting bogged down in the "what if?" questions, Johnson's film stays above the fray. Although it does dip its toe in a trope or two, it manages to avoid many of them. In honor of Looper's smart storytelling, Wired is taking a trip back in time to revisit some the best time-travel flicks of the past. Click through the gallery above for a guided tour of some of the finest space-time-shifting tropes on film.

Blowback: What's Your Favorite Time-Travel Trope in Movies?

Think we missed something? Hit the comments and sound off on other great time-travel pitfalls that can snarl a plot.