[Everyneurotic]

wiki knows:

http://en.wikipedia.org/wiki/Hollow_earth

Fantastic stories (supposedly believed as factual within fringe circles) have also circulated that Hitler and some of his followers escaped to hollow lands within the Earth after World War II via an entrance in Antarctica.

and

Opponents of the hollow Earth theory suggest, although without historical documentation, that Adolf Hitler, influenced by hollow-Earth ideas, actually sent an expedition in an unsuccessful attempt to spy on the British fleet by aiming cameras up into the sky. The accuracy of such rumors remains questionable; some supporters of the hollow-Earth theory feel that their opponents deliberately bring Hitler into the picture in order to discredit the theory.