With X-Men: Apocalypse set to release this month, it’s worth taking a look back at the storyline that really elevated the titular character’s status. Kicking off the fabled “Age of Apocalypse” story, 1994’s X-Men: Alpha introduced a generation of readers to one of Marvel’s most ambitious stories to date and the concept of a radically altered Marvel Universe.

Backing up a bit: the mutant Apocalypse had been introduced years earlier in Marvel’s X-Factor title as an uber-ambitious mutant terrorist. As his history developed over the years, he was gradually revealed to be one of Marvel’s oldest mutants whose origins could be traced back to ancient Egypt. (He was retroactively revealed to have been involved in some of Marvel’s key moments and was even hinted to have been behind Wolverine’s metal skeleton.) Immensely powerful, the X-Factor and the X-Men nevertheless defeated him time and again.

In 1993, the X-Men’s “Legion Quest” story had Charles Xavier’s mutant son go back in time in an attempt to kill Magneto before he could rise to power and ruin mutant reputations in the future. Legion mistakenly killed his father instead, and worse, Apocalypse witnessed Legion’s efforts and decided it was time to rise to power. In a world where Marvel’s heroes hadn’t risen yet, and with no Xavier to form the X-men, how would the Earth survive an early assault by Apocalypse?

Back in 1994, we didn’t have much of an internet and online forums to speculate on what was happening. We only knew that every X-Men title was cancelled and was going to be replaced with twisted versions of themselves. Joe Madureira’s cover to X-Men: Alpha was our first glimpse of a twisted world where the X-Men still formed, but under different circumstances. Heroes were now villains; villains were now heroes; and Apocalypse was king. Glancing at a cover like this, we could only guess at what was happening.

For example, there’s a giant Apocalypse in the background, and since the story was called “The Age of Apocalypse,” we knew this was indicative of his takeover of the world. But what was the rest of the cover telling us? There’s Wolverine, but he’s only got one hand. Sabretooth is there with a much smaller character chained to himself (you needed to be up on your Marvel history to know who the little guy was). The purple girl resembled Blink, the hero of Generation X who died in their origin story. It made sense that dead characters might still be alive in an alternate universe.

Magneto’s in the background, but he appears to be standing with Rogue. Why? And who’s that flaming figure in front of them? There’s Quicksilver, but where’s his sister, the Scarlet Witch? What about the bald guy behind Wolverine? (Look carefully, and you can tell who he is.) What’s with those green robots?

And that’s just a glimpse of what we were in for. The comic inside got weirder, and the assorted spinoff series even more than that. We were introduced to a world where Apocalypse lived up to his name and turned the world to waste, with only a small band of mutants standing in his way. The Age of Apocalypse is worth a look in advance of this summer’s movie for one of the best stories about this character, and it all started with this cover.

(Note: The image here is a recent reprint, which shows up much better than the original chrome cover Marvel used for this in 1993.)