The 'Altstadt' or old town, located between the Rhine and Heinrich-Heine-Allee, is the heart of Düsseldorf. This pedestrian zone is said to be the 'longest bar in the world' and most of the city's out- and indoor-events take place here, i.e. the Düsseldorfer Altstadt-Herbst, an end-of-summer festival.
...Dusseldorf Travel Guide.