This is the 3773rd most frequent German word.
ruhrgebiet
The "Ruhrgebiet" is the Ruhr region in Germany, an urban industrial area in North Rhine-Westphalia.
In this sentence, 'Ruhrgebiet' refers to a geographical region in Germany, used as a proper noun.
Das Ruhrgebiet ist bekannt für seine industrielle Geschichte.
The Ruhr area is known for its industrial history.
Here, 'Ruhrgebiet' indicates a location where the action of meeting friends took place, showing its utility as a locational context.
Ich habe viele Freunde im Ruhrgebiet kennengelernt.
I met many friends in the Ruhr area.
In this instance, 'Ruhrgebiet' serves to discuss the subject's characteristics and evolution over time as a historical subject.