Cologne (, Kölsch: "Kölle") is a city on the Rhine River in the state of North Rhine-Westphalia in Germany. About 1,060,000 people live there, making Cologne the biggest city in North Rhine-Westphalia. It is in the southern part of the 'Rhine-Ruhr agglomeration' of cities with a combined total population of about 10 million people. This is one of the most densely populated areas of the world.