One of my favorites was "Vorlesungsverzeichnis" (lecture directory/course catalog).

Vorlesung = lecture

- Lesung = a reading (like a book reading)/lesson

- add "Vor" ("before" as in "in front of [a group]") and it becomes Lecture

Verzeichnis = directory

- Zeichnis = symbol, signal, reference, sign

- add "Ver" (hard to really explain what it does) and it becomes directory, index, register, list

German is considered an inflective language, because it uses just one suffix for words, and that suffix has many-many variants to express the required grammatical meaning (singular/plural, modality, subject/object, dative/accusative, genitive, etc.)

Agglutinative languages just jam everything after the word in small morphemes. (And some, just to be sure, has a few variants of each of those, to match vowel kinds and such.)