Cologne is the fourth-most populous city of Germany and the largest city of the German state of North Rhine-Westphalia with nearly 1.1 million inhabitants in the city proper and over 3.1 million people in the Cologne Bonn urban region. Cologne is also part of the Rhine-Ruhr metropolitan region, the second biggest metropolitan region by GDP in the European Union. Centered on the left bank of the Rhine, Cologne is located on the River Rhine, about 35 kilometres (22 mi) southeast of the North Rhine-Westphalia state capital Düsseldorf and 22 kilometres (14 mi) northwest of Bonn, the former capital of West Germany.