Its capital is Düsseldorf; the largest city is Cologne. Four of Germany's ten largest cities (Cologne, Düsseldorf, Dortmund, and Essen) are located in this state, as well as the second largest metropolitan area on the European continent, Rhine-Ruhr. Beethoven, Heinrich Heine or Joseph Beuys - Germany's most populous land has seen the birth of many well-known artists and is one of Europe's great cultural regions. Museums, theaters, orchestras and concert halls, musicals and other events attract millions of visitors every year. In addition to these cultural achievements, there are four World Heritage sites: Cologne Cathedral, Aachen Cathedral, Augustusburg Castle in Brühl and Zollverein Mine in Essen. The symbol of Cologne is even the most visited curiosity of Germany.