Drums Along the Dusseldorf - S3-E30
Factual error: All through this episode, characters keep referring to the river the bridge *du jour* spans as "The Düsseldorf" or "Düsseldorf river." The city of Düsseldorf is situated on the river Rhine - there is no "Düsseldorf river." It's a well known fact that the producers were hardly geography whizzes, but not knowing the Rhine is bad even by their standards. Curiously enough, there kinda is a "Düsseldorf river" called the Düssel, and it meets the Rhine there. The Düssel however is a small streamlet that a well-trained man could probably jump over - so the mistake is still a valid one.
Answer: It's a comedy, not a documentary.
stiiggy
Perhaps it was counterfeit. There are numerous episodes where they deal in counterfeit monies.