Perhaps the pre-Adamic earth. Have you considered that?
I do not believe in a race of humans pre-Adam. But I do believe the angels inhabited this place before the rebellion. A lot of scriptures seem to point to that. In Genesis, it says that the earth "became" without form and void. And in another scripture, it says that God didn't originally create the earth void. So it makes sense that it was created perfect and then somehow became without form and void. When God created man/Adam, He instructed him to keep the garden ... because satan/lucifer had already fallen.
Just some things to consider....
