Age of Apocalypse

"Age of Apocalypse" is a 1995 comic book crossover storyline mostly published in the X-Men franchise of books by Marvel Comics. The Age of Apocalypse briefly replaced the universe of Earth-616 and had ramifications in the main Marvel Comics universe when the original timeline was restored. It was later retconned as having occurred in the alternate universe of Earth-295.

During the entirety of the Age of Apocalypse event the regularly published X-Men comics were replaced by new X-Men related mini series, focusing on various teams and individuals in the Age of Apocalypse world including X-Calibre, Gambit and the X-Ternals, Generation Next, Astonishing X-Men, Amazing X-Men, Weapon X, Factor X, X-Man and X-Universe. The event was bookended by two one shots, X-Men Alpha and X-Men Omega.

The storyline starts with Legion (David Haller), a psychotic mutant who traveled back in time to kill Magneto before he can commit various crimes against humanity. Legion accidentally kills Professor Charles Xavier, his father, leading to a major change in the timeline. The death of Professor Xavier leads Apocalypse to attack 10 years sooner than he did in the original timeline, taking control of Earth and altering everything that happened from that point forward. Apocalypse is opposed by several factions of mutant resistance, including a group led by Magneto. The group manages to send the mutant Bishop back in time to prevent the murder of Professor Xavier, undoing the entire timeline.

In 2005, Marvel published an Age of Apocalypse one-shot and miniseries to celebrate the 10th anniversary of the fan favorite event. The book looks at what happened after the end of the original story, revealing that the timeline became in fact an alternate earth, designated "Earth-295". The "Dark Angel Saga" in 2011 revisited the alternate reality once more, leading to an Age of Apocalypse ongoing series launched in 2012 that ran for 14 issues. The world was also featured as part of Marvel's 2015 Secret Wars.