"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.
Cover of Age of Apocalypse #1 (May, 2012). Art by Humberto Ramos.
The X-Men are a superhero team appearing in American comic books published by Marvel Comics. Created by writer/editer Stan Lee and artist/co-plotter Jack Kirby, the team first appeared in The X-Men #1. Although initially cancelled in 1970 due to low sales, following its 1975 revival and subsequent direction under writer Chris Claremont, it became one of Marvel's most recognizable and successful franchises. They have appeared in numerous books, television shows, 20th Century Studios's X-Men films, and video games. The X-Men title may refer to the superhero team itself, the eponymous comic series, or the broader franchise including various solo titles and team books such as the New Mutants, Excalibur, and X-Force.
Variant cover of X-Men (Vol. 6) #2 (October 2021) depicting the first elected Krakoan X-Men team (clockwise from left): Synch, X-23, Sunfire, Marvel Girl, Rogue, Polaris, and Cyclops. Art by Mahmud Asrar.
The original X-Men members that were created by Stan Lee and Jack Kirby, showing their original design
Giant-Size X-Men #1 (May 1975). Cover art by Gil Kane and Dave Cockrum.
Uncanny X-Men #227 (March 1988) by Chris Claremont and Marc Silvestri