Board Thread:General Discussion/@comment-28125426-20161216223720/@comment-1257201-20161216231725

Just to clarifY: In the early Earth Prime stories (from 1968 until 1978), Earth Prime was explicitly stated to be our earth, on which was located all the readers of DC Comics as well as the writers and editors, including a few writers and editors (Julius Schwartz, Cary Bates, Elliot S. Maggin) who had personally encountered heroes from other Earths. When Ultraa was introduced (1978), one could suppose that our Earth really did have a secret super-hero.

However, the events of "Crisis on Earth-Prime" (1982) are more problematic. Worst of all, Earth Prime was destroyed in 1985 or 1986 -- and I think it's safe to say that this did not actually happen here. Yet in pre-Crisis continuity, the Earth-Prime of 1985 was clearly intended to be the same place that Flash discovered in 1968. So I think we must conclude that this never was "our" world at all.

(The Earth-Prime of the Threeboot Legion is yet another, unrelated, world.)