Geography and urban development of Dresden past 60 years has made Dresden the fourth largest urban area in Germany after Berlin, Hamburg, and Cologne. The most important river in Dresden is the Elbe river, the only navigable body of water to flow through the city. There are also a number of tributaries such as the river Weißeritz. The nearest German cities are Chemnitz (80 km to the southwest), Leipzig (100 km to the northwest) and Berlin (200 km to the north). The Czech capital Prague is about 150 km to the south; the Polish city of Wrocław is about 200 km to the east. There are
Accession of Hamburg to the German Customs Union (Zollverein) that were previously uncompetitive, now grew extensively. The citizens of Hamburg were driven to make use of articles of German origin much more freely than before, as many of them were cheaper than corresponding foreign articles which were now weighted with a Customs duty. As predicted, the new conditions favoured the development of manufactures in Hamburg itself. With the free port, Hamburg became the leading port in continental Europe and the world's fourth largest after New York, London and Liverpool. This continued the increase of trade prior to the accession, which in 1873- 1887 grew by 44.2%. Nevertheless, outside the