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.

Mülheim an der Ruhr was first mentioned in documentation in 1093 and grew out of two historical settlement centers, Broich Castle on the left and the church hill on the right side of the Ruhr. It received its town charter in 1808. At around 1770 industrialization began in Mülheim with the expansion of the Ruhr into a shipping route, yet between 1850 and 1890, it changed from a shipping to an industrial location. For the first time in the Ruhr area, steel production with coking coal started in 1849 at Friedrich-Wilhelms-Hütte and the first briquette factory in the Ruhr area opened at the Wiesche colliery in 1861. In the course of 1943 and 1944 the city was repeatedly targeted by air raids. The main destinations were the city center, the railway lines, the German pipe works, the Schmitz-Scholl company as a supplier of provisions for the Wehrmacht, the Reichsbahn repair shop and the harbor. The attack left 530 dead of the city's population and 1,630 buildings (64%) were destroyed or damaged. Around 40,000 residents then had to be evacuated.

In 1966 Mülheim was the first city in the Ruhr Area to become completely free of coal mines, when its last coal mine "Rosenblumendelle" was closed. The former leather and coal city had successfully made a complete transformation to a diversified economic centre. Although Mülheim suffered badly during the war, it has survived the war much better than the other cities I have visited in the Ruhr area. The Altstadt is still made up of many streets with houses and other buildings from the late nineteenth, early twentieth century. Mülheim currently has a population of 170,000 inhabitants.