Düsseldorf is an important business centre, particularly for advertising, fashion, telecommunications and trade fairs. K20 is an important modern art gallery, while K21 is for contemporary art. Rheinturm offers views from almost 300 metres, while the Aquazoo specializes in marine animals. Königsallee is one of the most important shopping streets, while its nightlife goes far beyond the albeit excellent beer "Altbier" served in the 260 pubs and taverns in the old quarter Aldstadt alone. Bolkerstrasse, Ratinger Strasse and Kurze Strasse are favourite nighlife locations.