The area of Jülich, Düsseldorf, Cologne (Köln), and Bonn is well connected with other areas in Europe via the airports of Düsseldorf (DUS), Cologne-Bonn (CGX), and Maastricht-Aachen (MST) as well as by frequent train connections. Also Frankfurt airport (FRA) with flights to many destinations all over the world is only a one-hour train ride from Cologne.
 

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... Aachen
... Bonn
... Cologne (Köln)
... Düsseldorf
... Eifel National Park
... Jülich
... Maastricht