Marvel Comics X-Men Alpha #1

X-Men: Alpha #1 is the landmark 1995 Marvel comic book that officially kicked off the legendary Age of Apocalypse crossover event. This double-sized issue—cover-dated February 1995 but released in December 1994—completely altered the Marvel Universe by introducing a dystopian alternate reality where Charles Xavier was killed before forming the X-Men, allowing the villainous Apocalypse to conquer North America.