Aachen (äˈkhən) [key], Aix-la-Chapelle ĕks-lä-shäpĕlˈ, or Bad Aachen bät äˈkhən, city (1994 pop. 246,570), North Rhine–Westphalia, W Germany, near the Belgian and Dutch borders. One of the great historic cities of Europe, it is now chiefly important as a rail and road hub and as an industrial center. Almost every branch of the iron and steel industry is represented in the area. Its manufactures include textiles, electrical goods, food (chocolate and candy), glass, machinery, rubber goods, metal products, and furniture. The city's hot mineral baths, frequented by the Romans in the 1st cent. A.D., are still used to treat gout, rheumatism, and skin diseases. Aachen is the site of a technical university and numerous other educational institutions. There are several cultural institutions, notably the Ludwig Art Forum, which exhibits modern art.
Charlemagne, who was probably born in Aachen in 742, made the city his northern capital and the leading center of Carolingian civilization. He built a splendid palace and founded the great cathedral, which contains his tomb. The cathedral, which has an octagonal nucleus modeled on the Church of San Vitale in Ravenna, Italy, received extensive Gothic additions in the 14th–15th cent. From 936 to 1531, German kings were usually crowned at Aachen. Treaties ending the War of Devolution (1668) and the War of the Austrian Succession (1748) were signed there (see Aix-la-Chapelle, Treaty of). It was occupied (1794) by French troops and later annexed (1801) by France. It passed to Prussia in 1815. At the Congress of Aix-la-Chapelle (1818) Czar Alexander I of Russia unsuccessfully proposed that the Holy Alliance be tightened. From 1918 to 1930 the city was occupied by the Allies as a result of Germany's defeat in World War I. During World War II approximately two thirds of Aachen was destroyed by aerial bombardment, and the city was the first major German city to fall (Oct., 1944) to the Allies.