The chief city of the Ruhr is Essen, a five-letter word. Essen is a city in North Rhine-Westphalia, Germany and is the ninth largest city in Germany. It is located in the central part of the Ruhr area, one of the largest urban areas in Europe. The city is known for its steel industry and is home to several large companies. It is also a cultural center, with many museums, theaters, and other attractions.