About Antarctica being "off limits": I don't know if this is the same type of thing as what you're talking about, but I once read a novel by W.A. Harbinson, called Genesis.
https://www.goodreads.com/en/book/show/1726142


I think it was sold as science fiction, but the author seemed to really believe what he was writing about, at least a little. I'm sure he made up a lot of names for characters, etc, for the purposes of storytelling, but he seemed pretty serious about the general topic he was writing about.

That topic was the idea that flying saucers had been invented by a sort of clandestine subset of Nazi scientists, back in WWII, and they had moved to a secret base in Antarctica when it became obvious that WWII was not going to work out well for them. There was some kind of American connection to the base... like, some high level people in the US were aware of it, but their hands were basically tied, for some reason, and they had to just let it be.

Also, there was at least one very high level character within the Nazi flying saucer community (that sounds funny to me, that phrase, "Nazi flying saucer community"... anyway) anyway there was a very high level guy in that community who was an American by birth, but he worked with the Nazis somehow. I don't remember all the specifics, but it was a pretty convincing and scary story to read.

There was also some very wretched stuff about the slave labor the Nazis used in Germany, mostly Jewish people of course, who were transported by U-boat to the secret base in Antarctica. So, that sucked to read.

Aaaanywho, this thread is about conspiracy theories, soooooo there ya go.