is a city in Germany. It is the largest city of Germany's most populous state of North Rhine-Westphalia (NRW) and the fourth-most populous city and one of the oldest in Germany. With 3.6 million people in the urban region and 1.1 million inhabitants within its city proper, Cologne is the largest city on the river Rhine and also the most populous city of both the Rhine-Ruhr Metropolitan Region and the Rhineland. Centered on the left (west) bank of the Rhine, Cologne is about 35 km (22 mi) southeast of NRW's state capital Düsseldorf and 25 km (16 mi) northwest of Bonn. It is classified as a GaWC Gamma+ world city.