North Rhine–Westphalia (nôrth rĪn-wĕstfālˈyə) [key], Ger. Nordrhein-Westfalen nôrtˈrĪn-vĕstˌfäˈlən, state (1994 pop. 17,759,000), 13,111 sq mi (33,957 sq km), W central Germany. Düsseldorf is the capital. The state is bounded by Belgium and the Netherlands in the west, Lower Saxony in the north and east, Hesse in the southeast, and Rhineland-Palatinate in the south. Situated in the lower Rhine plain, North Rhine–Westphalia includes the Teutoburg Forest and the Rothaargebirge. It is drained by the Rhine, Ruhr, Wupper, Lippe, and Ems rivers. A highly industrialized state, it contains the largest industrial concentration in Europe (see Ruhr district), with one of the largest mining and energy-producing regions in Europe. It has excellent transportation facilities, including superhighways, electrified rail service, river transport, and two large airports. Its manufactures include chemicals, machines, processed foods, textiles, clothing, and iron and steel. More than half of the state's total land is occupied with commerical farming as well as gardens and orchards, although these enterprises amount to only a small portion of the area's gross annual product. North Rhine–Westphalia is also the most populous state in Germany and has numerous large cities, including Aachen, Cologne, Düsseldorf, Duisburg, Essen, Dortmund, Remscheid, Oberhausen, and Wuppertal. There are universities at Bielefeld, Bochum, Bonn, Dortmund, Düsseldorf, Cologne, and Münster. The state was formed in 1946 through the union of the former Prussian province of Westphalia, the northern part of the former Prussian Rhine Province, and the former state of Lippe. It possesses little historic unity because of significant cultural differences among the various peoples in the state; this diversity has been enlarged by substantial immigration from other European countries to cities throughout the region.