What as the ruhr valley?

The Ruhr Valley is a significant industrial region in Germany, primarily located in North Rhine-Westphalia. It emerged as a major center for coal mining and steel production during the 19th and early 20th centuries, contributing significantly to Germany's economic growth and industrialization. The valley has undergone significant transformation since the decline of heavy industry, now focusing on technology, services, and cultural development. Today, it is recognized for its urban diversity and as a UNESCO Global City of Culture.