The Ardennes (Dutch: Ardennen) is a region of extensive forests, rolling hills and old mountains formed on the Givetian (Devonian) Ardennes mountains, primarily in Belgium and Luxembourg, but stretching into France (lending its name to the Ardennes département and the Champagne-Ardenne région), and geologically into the Eifel. In Wallonia, the word 'Ardenne' in the singular is commonly used and is the origin of the powerfull industry in this region. In France, the word 'Ardennes' in the plural, together with the definite article, is commonly used to refer to the French Department of that name.
Much of the Ardennes is covered in dense forests, with the old mountains averaging around 350-500 m (1,148-1,640 ft) in height but rising to over 650 m (2,132 ft) in the boggy moors of the Hautes Fagnes (Hohes Venn) region of north-eastern Belgium. The region is typified by steep-sided valleys carved by fast-flowing rivers, the most prominent of which is the Meuse. Its most populated cities are Verviers in Belgium and Charleville-Mézières in France, both exceeding 50,000 inhabitants. The Ardennes is otherwise relatively sparsely populated, with few of the cities exceeding 10,000 inhabitants with a few exceptions like Eupen or Bastogne.
The Eifel range in Germany adjoins the Ardennes and is part of the same geological formation, although they are conventionally regarded as being two distinct areas.
The region took its name from the ancient Arduenna Silva, a vast forest in Roman times, that stretched from the Sambre river in Belgium to the Rhine in Germany. The forest was named after a pagan goddess Arduinna. The modern Ardennes covers a much smaller area.
The highly strategic position of the Ardennes has made it a battleground for European powers for centuries. The region repeatedly changed hands during the early modern period, with parts or all of the Belgian Ardennes being incorporated into France, Germany, the Spanish Netherlands, the Austrian Netherlands and the United Kingdom of the Netherlands at various times. In the 20th century, the Ardennes was widely thought unsuitable for large-scale military operations due to its difficult terrain and narrow lines of communications. However, in both World War I and World War II, Germany successfully gambled on making a rapid passage through the Ardennes to attack a relatively lightly defended part of France. The Ardennes saw three major battles during the world wars – the Battle of the Ardennes in World War I, and the Battle of France and Battle of the Bulge in World War II. Many of the towns of the region were badly damaged during the two world wars.
The rugged terrain of the Ardennes severely limits the scope for agriculture, with arable and dairy farming in cleared areas the mainstay of the agricultural economy. The region is rich in timber and minerals, and Liège and Namur are both major industrial centres. The extensive forests have an abundant population of wild game. The scenic beauty of the region and its wide variety of outdoor activities, including hunting, cycling, walking and canoeing, make it an important tourist destination.