The German language has one feature which differs from most other languages, which is that you can combine two nouns to a new word, for example
Schiff can become
Dampfschiff and together with Fahrt it becomes
This method can bring up some really long words, which is unfortunately very common in official community documents, for example
While this is sometimes annoying, when you try to understand those official documents, it can be quite funny if you do it intentionally and produce some artificial, yet perfectly valid new nouns (on a side note, leading to the assumption, that the number of German words is infinite...).
For example, here my personal favorites:
Großglocknerhochalpenstraßenbahnwärterhäuschen [46 letters]
(Großglockner = the highest mountain in Austria, Hochalpen = the High Alps, Straßenbahn = tramway, Wärter = guardsman, Häuschen = a small house)
But my question is: which real-world German word is the longest? There should be evidence that the word is really commonly used.
Since there was a discussion about this question in the comments and it's about to be closed - I try to rescue it by giving it a new direction (and rephrased the question):
I'm looking for real long words, which may be uncommon and funny, but still are "valid" in the sense, that they may really exist and are not artificially lengthened without having any meaning of sense.
(So my own example might not be the best, even though the word itself could exist very well in the case that the Großglockner Hochalpenstraßen AG decides to build a tramway as well and give their guards a little house to hide from the cold weather outside...)