Supposedly, the Germans had a subterranian Antarctic UFO base in the 1930's. Even sent crews to mars in 1938 or 1939.
They were the ones that said you could make your own space vehicle powered by two air-cooled VW engines, that the moon atmosphere was "thin" but didn't require any breathing apparatus and that the temperature was "cool" but only required sturdy (wool) clothing.
I actually sent away for the plans for the space vehicle but got my letter back as "no such person at that address." I guess they had to leave.
I got my plans from these folks- used a motor out of a early 60's bug and a micro bus. The kids, old lady and me quit going to the lake a couple years ago cause it was crowded, no most weekends we take the space craft to the moon.
Only problem is I have to relash the valves every 10,000 miles, so we have a few stops on the way.