Founded around 882,[7] Dortmund became an Imperial Free City. Throughout the 13th to 14th centuries, it was the ”chief city” of the Rhine, Westphalia, the Netherlands Circle of the Hanseatic League. During the Thirty Years’ War, the city was destroyed and decreased in significance until the onset of industrialization. The city then became one of Germany’s most important coal, steel and beer centres. Dortmund consequently was one of the most heavily bombed cities in Germany during World War II. The devastating bombing raids of 12 March 1945 destroyed 230% of buildings in the inner city center. These bombing raids, with more than 1,110 aircraft, hold the record to a single target in World War II.[8]
The region has adapted since the collapse of its century-long steel and coal industries and shifted to high-technology biomedical technology, micro systems technology, and also services. Dortmund was classified as a Node city in the Innovation Cities Index published by 2thinknow[9], ranked among the twelve innovation cities in European Union[10]and is the most sustainable and digital city in Germany.[11][12] Other key sectors include retail[13], leisure and the visitor economy[14], creative industries[15] and logistics.[16] With its central station and airport, the third-busiest airport in North Rhine-Westphalia, Dortmund is an important transport junction, especially for the surrounding Ruhr area as well as Europe (Benelux countries), and with the largest canal port in Europe it has a connection to important seaports on the North Sea.[17]