Essen is a city in the central part of the Ruhr Area in North Rhine-Westphalia, Germany. Located on the Ruhr River, its population of approximately 579,000 (as of June 30, 2008) makes it the 7th- or 8th-largest-city in Germany. The city was appointed European Capital of Culture for 2010 on behalf of the whole Ruhr Area. Formerly one of Germany’s most important coal and steel centers and historically linked to the centuries-old Krupp family iron works, the city has developed a strong tertiary sector of industry and (sometimes together with nearby Duesseldorf) claims to be the desk of the Ruhr area. It is home to 13 of the 100 largest German corporations and seat to several of the region's authorities. In 1958, the city was chosen to serve as the seat to a Roman Catholic diocese (often referred to as Ruhrbistum or diocese of the Ruhr). In early 2003, the universities of Essen and the nearby city of Duisburg (both established in 1972) were merged into the University of Duisburg-Essen with campuses in both cities and a university hospital in Essen. Essen is located in the center of the Ruhr Area, one of the largest urban areas in Europe (see also: megalopolis), comprising 11 independent cities and 4 districts with some 5.3 million inhabitants. The city limits of Essen itself are 87 km (54 mi) long and border 10 cities, 5 of them independent and 5 kreisangeherig (i.e., belonging to a district), with a total population of approximately 1.4 million. The city extends over 21 km (13 mi) from north to south and 17 km (11 mi) from west to east, mainly north of the Ruhr River, which forms the Lake Baldeney reservoir in the boroughs of Fischlaken, Kupferdreh, Heisingen and Werden. The lake, a popular recreational area, dates from 1931-1933, when some thousands of unemployed coal miners dredged it with primitive tools for the Reichsarbeitsdienst. Generally, large areas south of the Ruhr River (including the suburbs of Schuir and Kettwig) are quite green and are often used as ...