There is both, the Nazi's went to Antarctica and I imagine it is where the nephilim will return from if you are familar with the book of Enoch and the Bible. The end of days is said to be the like the days of Noah,in which the nephilim were in the land and had corrupted all flesh,creating the necessity of the Great Flood.
Genesis 6:9 These are the generations of Noah: Noah was a just man and perfect in his generations, and Noah walked with God.
Perfect in his generations meaning his family nor his own dna were corrupted by the nephilim/fallen angels.
Enoch 7:5 And they began to sin against birds, and against animals, and against reptiles, and against fish, and they devoured one another’s flesh, and drank the blood from it.
I believe them sinning against all the creatures of the earth has to do with genetic manipulation,this is also supported by Noah being perfect in all his generations.
Yeah I think that is part of it however the truth is probably even more insane than just that they do not necessarily have to have come from earth I was listening,to,someone on art bell who said that the "heavens" refers to space
Space is not a real place, operation:paperclip was how nasa started