The Ruhr area ('Ruhrgebiet') is named after the river that borders it to the south and is the largest urban area in Germany with over five million people. It is mostly known as a densely-populated industrial area. By 1850 there were almost 300 coal mines in operation in the Ruhr area. The coal was exported or processed in coking ovens into coke, used in blast furnaces, producing iron and steel. Because of the industrial significance, it had been a target from the start of the war, yet "the organized defences and the large amount of industrial pollutants produced a semi-permanent smog or industrial haze that hampered accurate bombing". During World War II, the industry and cities in the Ruhr area were heavily bombed. The combination of the lack of historic city centres, which were burned to ashes, and (air) pollution has given the area and the cities a bad reputation. Especially because it is so close to the Netherlands, I thought it would be an interesting area to visit for a little trip. I have spent three nights at a campsite on the Ruhr and visited six cities.

Dortmund is the largest city in the Ruhr area. It has a population of almost 590,000 inhabitants, making it the eighth largest city in Germany. Dortmund was founded around 882. Throughout the 13th to 14th centuries, it was the "chief city" of the Rhine, Westphalia, and 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. The town expanded into a city, with the population rising from 57,742 in 1875 to 379,950 in 1905. Sprawling residential areas like the North, East, Union and Kreuz district sprang up in less than 10 years. 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 98% 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. Post-war, most of the ancient buildings were not restored, and large parts of the city area were completely rebuilt in the style of the 1950s. A few historic buildings as the main churches Reinoldikirche and Marienkirche were restored or rebuilt, and extensive parks and gardens were laid out. The simple but successful postwar rebuilding has resulted in a very mixed and unique cityscape.