Well, almost any fictional universe set on Earth is an alternate history. It'd be organized like a timeline, as I do enjoy the use of a timeline to illustrate segments in time.
WWII would of course be a major period in the history of this world, not only every corner of the world experiencing war, but it would be during this time that we first begin seeing 'supermen' as the result of a genetic arms race. Steroids, Eugenetics, etc. all had been contributing up to that point. Some 'supermen' where the result of independent organizations, others where not so much, with the Nazis having created what we'd come to know as the Supersoldier, however, like the Semi-Stealth Bomber, or Jet Planes such would have entered he war too late to alter the outcome.
Then would come the atomic age, and with that age would come awareness of what we'd know as mutants (drugs, radiation, biogenetic agents, all scabling someone's genome at birth). Most of the early one's would be negative though by the late sixties, or seventies we'd be seeing more of what we'd consider super powers rise in the population.
