I just found this and found it utterly fascinating as it ties into my own Journey to the Center of the Earth stories, as well as Rocketman.
The Nazis spent millions, which would be equivalent to billions in today's money, to find ways beneath the earth, to establish contact with a higher civilization and gain power.
The Antarctic was just one center of operations for them and the inspiration for many tales of terror.
I suspect that this video has many truths within it, along with speculation.
Just like the Kennedy Assassination, we may never know the whole truth and those who do, are not talking...at least in public and if they are...as usual, they are discredited.
It's not to the advantage of modern governments or religion to acknowledge that there could be older, higher developed civilizations on our planet or another.