Here's the official trailer of X-men: Days of Future Past which is set to come out on May 23, 2014. It's the sequel to X-Men: First Class and a bridge to the original X-men film trilogy. In here, the characters from the original X-Men film trilogy join forces with their younger versions in order to change the past and save the future. The future X-men send Wolverine to the past in order to change history and the consequence for both mutant and mankind.