I'm reading more about the DCU

[ratcreature]

If you ever feel a desire to become incredibly confused in an incredibly short amount of time, I recommend reading The Annotated Crisis on Infinite Earths and The Infinite Atlas (becoming confused works probably best when you're unfamiliar with DC continuity like I am, the site itself is really quite organized and helpful). There you can get a cool overview of Earth-Prime, Earth-1 to 4, Earth-S, Earth-X, Earth-C and Earth-C-, Earth-12, Qward, The Fifth Dimension (those would be the major universes pre-Crisis according to the site) as well as Alternate Earth-1 and 2, Earth-15 and 17, Earth-A, B, G, and Q, Earth-Omega, Earth-Quality, Crossover Earth, and Mirror Earth (those would be minor ones), and that apparently doesn't cover the Earths of Interregnum Universes (whatever that is), Elseworlds, Imaginary Stories, Future Timelines, Hypertimelines...

At least now I'm really clear on why it is named "Crisis on Infinitive Earths."