as a matter of fact bielefeld conspiracy is a misunderstanding. a guy said he's from bielefeld and the person replied "das gibt's doch gar nicht" meanng i don't believe it but can also be confused with that does not exist implying that bielefelddoes not exist and it took off from there.
The Europa-Park in Rust claims that they had 5.6 million tourists in 2017. That would make the small village Rust number 6 of this list. Just said. ;-)
For this type of quiz a tourist is someone who stays overnight. And that's the best way to get a number. You couldn't distinguish commuters from tourists or people passing through otherwise. Most people don't stay in a hotel of the theme park or leave after a day.
Assuming roughly the same % of visitors stay on property as the rough ratio I found for Disney World (35%), just under 2,000,000 people stay the night each year in Rust, barely missing the top 10. Of course, in all likelihood, fewer people stay overnight than Disney World as it is a much smaller park, but it doesn't really matter at this point.
Aha! Source data is overnight stays, so doesn't include day-trippers but does include business travel. Explains a lot of the mis-matches vs tourist/sightseeing destinations