(CBR) In movies, time travel is the quantum equivalent of a Band-Aid, one that cinema often applies to correct futures of the post-apocalyptic variety.

From AI-controlled killing machines to disease-ravaged worlds, righting wrongs by breaking the laws of physics is a popular trope that yields some truly memorable sci-fi. Fox’s blockbuster "X-Men: Days of Future Past" is the latest film to pull a "Quantum Leap," as Wolverine travels back in time to save both humans and mutants from the deadly Sentinels.

As director Bryan Singer’s sequel passes $500 million at the global box office, SPINOFF ONLINE takes a look back at five movies that used time travel to fix terrible futures.