Went on a schizo deepdive into the Ahnenerbe rabbit hole last night.
There's a spring type thing under the ice sheet in Antarctica that is always 18° and this warm water has channelled out these waterways under the ice. And that bits natural.
Apparently there were up to 100 German U-boat's unaccounted for at the end of the war and the tinfoil answer is they went to Agartha and met with either time travellers or aliens that gave them advanced technology, including saucers
I didn't know that iirc it was op highjump where about thousand American military personnel went there in the 30s. The idea they were floating was that this was the third front of the war and the Germans conceded Germany, partly because the time traveling underwater aliens are the original Aryans.
Iran has just recently stated that they are going to put a base at the south pole.
This is likely crap as there are some articles but the only person I saw say it was on memri TV and half the time I think that's satire.