It Happened Here
Note - I'm republishing this 2003 review from my old web site since I just read in the DVD Savant's web site that the DVD of this film is once again commercially available.
This is probably the best example of "alternate history" I've seen on film: what would England have been like had Hitler invaded and won WWII? We follow an apolitical Irish nurse who moves to a bombed out London only to find that the only way she can practice her trade is to joint the Party and become a cog in the Nazi pacification machine.
Produced over a seven year period by a young team of filmmakers and released in the early 1960's, the film has gathered a cult reputation of sorts, and even some controversy, given its presentation of the complicity of the English public with the Nazi occupiers. No matter; the film stands on its own as a superbly crafted and chilling presentation of What Might Have Been.
The grainy black and white image suits the material extremely well, as does the use of dilapidated urban neighborhoods. The amount of detail shown via placards, signs, uniforms, and even radio broadcasts also adds to the overall effect. But what is most telling is the matter of fact presentation of Nazi brutality and its extension into English society.
Unfortunately, there are no extras on the DVD; surfing the web, though, one can locate a good amount of information about the film and its producers.