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
Dresden the communist era to avoid nationalisation, Dresden was one of the most important German cities, an important industrial centre of the German Democratic Republic. The period of the GDR until 1990 was characterized by low economic growth in comparison to western German cities. In 1990 Dresden had to struggle with the economic collapse of the Soviet Union and the other export markets in Eastern Europe. After reunification enterprises and production sites broke down almost completely as they entered the social market economy, facing competition from the Federal Republic of Germany. After 1990 a completely new legal system and currency system