George Sewell plays two parts in this movie; he is a German officer, seen at the film's climax, and also briefly plays Adolf Hitler.
The actual title for raid was Operation Anthropoid.
This movie was one of the few productions (besides several made in Russia and Yugoslavia) which took the time and the effort of duplicating WW2 German Tiger tanks. The only other American production who did this was De l'or pour les braves (1970), until Steven Spielberg did the same for his movie Il faut sauver le soldat Ryan (1998).
Since the film was set in Czechia, the filmmakers made use of Czech army equipment such as OT81 half tracks which are very similar to their war time predecessor, the German Sdkfz 251/1.