In the original series Star Trek episode Patterns of Force, the USS Enterprise arrives on an alien planet to find it is ruled by a Nazi regime. Patterns of Force includes the indelible image of Captain Kirk and Mr. Spock dressed in SS uniforms.
The episode originally aired in 1968, just two decades after the end of WWII, and the Germans were still pretty antsy about the whole Nazi business. As a result, Patterns of Force never aired in Germany. It showed up on pay TV - where anything can go - in the mid-90s. But it wasn't until last week that the episode aired on regular German TV, albeit after 10pm and with a warning that it wasn't suitable for younger children.
Interestingly the repression of the episode meant that it was only dubbed in German in 1995, so I wonder if the voices are very different from other episodes of the original series - perhaps a German Trek fan can help us out with this one?
Also, Patterns of Force gave us this: