So many oddities and quiddities!
They say Elijah was caught up to Heaven still alive. That Enoch was given the Grand Tour and 'walked with God'.
That implies that Heaven existed at the time (if you're a Christian). Must have been pretty empty, since according to Christians nobody could get there before Christs' death and resurrection. According to a Jewish friend of mine, there will be an eventual Judgement, after which all the 'good' Jews will spend eternity studying Torah (he also says that in his case that would involve several centuries of Remedial Hebrew).
There is also the (non-Biblical) Harrowing of Hell, mentioned in Dante and depicted in the York Mystery Play cycle. That's where, during his three-day 'death', Christ descends into Hell with Michael and a detachment of the Heavenly Host (Angelic SAS, or just the Heavenly Marine Corps?), grabs a bunch of Old Testament 'good guys', as well as Adam and Eve, and carts them off to Heaven (sorry about the wait, guys).
Then there may or may not be a Rapture. Followed (or not) by a Tribulation, followed (or not) by a millennium of Christs' rule. One presumes that everyone born in and living through said Millennium will be saved because if He's there ruling, you kinda have to believe in Him! Then a big battle, then God Himself arrives and does some serious Judging.
But why? All the Saved are already in Heaven, all the Damned already in Hell. The Millennials are all automatically saved and the forces of Hell have been routed. Judgement has already been made.
I think I'll wait for the Fimbulwinter!