Köln is a city located in the German state of North Rhine-Westphalia, on the banks of the Rhine River. It is the fourth largest city in Germany and is the largest city in the Rheinland region. Köln is known for its many historical landmarks, such as the Cologne Cathedral, which is one of the most visited tourist attractions in Germany. The city is also home to a vibrant cultural scene, with numerous museums, galleries, and theatres.