13. Bryan Singer based the time travel in the film on
string theory: "Until an object is observed, it hasn't really happened
yet. The time-traveller whose consciousness travels through time I call
The Observer, and until the Observer returns to where he travelled from,
the result hasn't occurred yet.
So he can muck about in the past and it isn't until he snaps back that the new future is set. As a result, we have parallel action, and there's underlying tension because there's always that threat Wolverine's consciousness could return to the future and leave the world in an even darker place."
14. For her role as Mystique, Jennifer Lawrence wore a special bodysuit. She had previously worn full-body prosthetics in X-Men: First Class (2011) but found that too uncomfortable.
15. This the first X-men film ever to be nominated for an Oscar (Best Visual Effects).