Cologne has a population of approximately 960,000 people, and is Germany's fourth largest city. Cologne is also the largest city in the German Federal State of North Rhine-Westphalia and within the Rhine-Ruhr Metropolitan Area. Cologne is home to the Cologne Cathedral, and is the seat of Roman Catholic Archdiocese. Cologne is also important because of its Kölsch beer. There are 12 Romanesque churches within Cologne that are examples of classic Medieval architecture. Most were heavily damaged during World War II and finally reached completion of the reconstruction process in the last decade of the 20th century. Cologne University hosts a student population of approximately 44,000 and is one of the largest universities in Germany. There are several museums, including El-De Haus, the former headquarters of the Gestapo houses, and a museum documenting Nazi rule, a special focus on the prosecution of political dissenters and minorities. Cologne in home to a Philharmonic Orchestra, a sports stadium that seats over 50,000 attendees, and a multi-function hall. A must see is the Schokoladenmuseum (Chocolate Museum), officially called Imhoff-Stollwerck-Museum