The Universum hallways were filmed in the newly built subway system in Prague.
The training place for artists is on the roof of shopping mall KOTVA, built in the 70's in the city centre of Prague (as very modern building at that time)
Some sources incorrectly state that it is an adaptation of one of Josef Nesvadba's 1960s short stories. It's not. Similarly to their previous collaboration on Zabil jsem Einsteina, panove (1970), Josef Nesvadba and Milos Macourek made the story up directly for the movie.
The "present time" of the film takes place in 1996. This can be calculated from the mentioned age of Klaus Abard, who, when meeting Nazis in South America, claims that he was 34 years old in 1944 and is now 86.
In 2011, Czech music band called "Kohout plasí smrt" recorded a song "Zítra ráno vstanu a oparím se cajem", directly inspired by this film.