Haha, Reminds me of some circle of rightwinged conspiracy theorists named the "Neuschwabenlandtreffen" in Germany. Their leader, Doctor Axel Stoll is quite infamous for his insane conspiracy gibble gabble.
They basically took the beforementioned hollow earth theory of Rolf Keppler and spiced with some esoteric Nazi bullshit - example: they think Hitlers still alive, residing along with his followers under Antartica in "Neuschwabenland". According to them "Nazi" comes from Narzareth, therefore Jesus was the first Nazi and the term used to be sacred. Also that the aryan race actually descends from an alien highly evolved civilisation, for example the straight hairstructure of the aryan race basically serve some kind of transmitter purpose and the Earth is some kind of punishment for all inferior races for the aryan alien civilisation to reign over. Another of their crazy theories is that all kinds of UFO sightnings are attributed to the so called "Reichsflugscheibe" (Nazi UFOs) - some kind of secret vehicle developed by the Nazis during the Third Reich.
Doctor Stoll (he died recently) and his followers used to meet in some pub in berlin to discuss their insane believes. Even the german constitution protection, who also classified Scientology as a cult/scam, won't take them seriously, even if they're observing the activities of the circle.