Flemish Diamond in the context of "Blue Banana"

The Rhine-Ruhr metropolitan region (German: Metropolregion Rhein-Ruhr) is the largest metropolitan region in Germany, with over ten million inhabitants. A polycentric conurbation with several major urban concentrations, the region covers an area of 7,110 square kilometres (2,750 sq mi), entirely within the federal state of North Rhine-Westphalia. The Rhine-Ruhr metropolitan region spreads from the Ruhr area (Dortmund-Bochum-Essen-Duisburg) in the north to the urban areas of the cities of Mönchengladbach, Düsseldorf (the state capital), Wuppertal, Leverkusen, Cologne (the region's largest and Germany's fourth largest city), and Bonn in the south. The location of the Rhine-Ruhr at the heart of the European Blue Banana makes it well connected to other major European cities and metropolitan areas such as the Randstad, the Flemish Diamond and the Frankfurt Rhine Main Region.

The metropolitan area is named after the Rhine and Ruhr rivers, which are the region's defining geographical features and historically its economic backbone.

North Rhine-Westphalia or North-Rhine/Westphalia, commonly shortened to NRW, is a state (Land) in Western Germany. With more than 18 million inhabitants, it is the most populous state in Germany. Apart from the city-states (Berlin, Hamburg and Bremen), it is also the most densely populated state in Germany. Covering an area of 34,084 km (13,160 sq mi), it is the fourth-largest German state by size.

North Rhine-Westphalia features 30 of the 81 German municipalities with over 100,000 inhabitants, including Cologne (over 1 million), the state capital Düsseldorf (630,000), Dortmund and Essen (about 590,000 inhabitants each) and other cities predominantly located in the Rhine-Ruhr metropolitan area, the largest urban area in Germany and the fourth-largest on the European continent. The location of the Rhine-Ruhr at the heart of the European Blue Banana makes it well connected to other major European cities and metropolitan areas like the Randstad, the Flemish Diamond and the Frankfurt Rhine-Main Region.

Mechelen (Dutch pronunciation: [ˈmɛxələ(n)] ; French: Malines [malin] ; historically known as Mechlin in English) is a city and municipality in the province of Antwerp in the Flemish Region of Belgium. The municipality comprises the city of Mechelen proper, some quarters at its outskirts, the hamlets of Nekkerspoel (adjacent) and Battel (a few kilometers away), as well as the villages of Walem, Heffen, Leest, Hombeek, and Muizen. The river Dyle (Dijle) flows through the city, hence it is often referred to as the Dijlestad ("City on the Dyle").

Mechelen lies on the major urban and industrial axis Brussels–Antwerp, about 25 km (16 mi) from each city. Inhabitants find employment at Mechelen's southern industrial and northern office estates, as well as at offices or industry near the capital and Brussels Airport, or at industrial plants near Antwerp's seaport.