Days of Future Past is a 1981 X-Men storyline (Published in Uncanny X-Men #141 and #142), written after the successful The Dark Phoenix Saga. This time-travel story was the first main story featuring Kitty Pryde.The story, written in 1980 and first published in early 1981, was set in 2013. The United States had become a dystopia, and people were divided into three groups: normal humans, normal humans with the mutant gene, and mutants. The first ones are free, the second are forbidden to have children, and the third are either killed or held in concentration camps, with collars that turn off their powers. Everything is run by the Sentinels. And Europe has atomic bombs, ready to blast the US as soon as the Sentinels attempt to go outside America. Nice 2013, isn't it?The group held in the concentration camp was composed of aged versions of the X-Men: Katherine Pryde, Ororo Monroe (Storm), Peter Rasputin (Colossus), Franklin Richards (the son of the Fantastic Four's Reed and Susan Richards), Rachel Summers (daughter of Cyclops and Jean Grey) and Magneto (now in a wheelchair). With the help of Wolverine, still on the loose, they managed to send Katherine Pryde back in time, placing her adult mind in the body of her teenaged 1981 version. She told the others that, on that day, the Brotherhood of Evil Mutants would kill the US senator Robert Kelly, along with Charles Xavier and Moira MacTaggert, which led to the anti-mutant hysteria.In the future (that is, the 2013 future), the X-Men escaped from the concentration camp, but had to leave Magneto behind, and Franklin died during the next Sentinel attack. They sneaked into the Sentinel headquarters, the Baxter Building (the former base of the FF), ignoring that the Sentinels allowed them to do so to capture and kill them. Wolverine, Storm and Colossus died. Only Rachel stayed outside, protecting the unconscious Kitty Pryde.In the present (meaning, the 1980 present), the Brotherhood broke into the Congress, but the X-Men turned up and took them out. Destiny left the fight and attempted to kill Kelly, but Pryde (whose mission all along was to prevent that) followed her and saved him. When she saved him, her adult mind returned to the future, restoring her teenaged identity.Several years later, Rachel Summers would go back in time as well, and stayed with the X-Men for a while. There were several mentions to the future involving her.The sequel to X-Men: First Class titled X-Men: Days of Future Past will be based on this story; however, it will be released in 2014, just missing the anniversary.
Days of Future Past contains examples of: