A stained glass window depicting the patron of the Cologne Cathedral, St Peter, at one of the Dom's windows. Cologne Cathedral (German: Kölner Dom, officially Hohe Domkirche St. Petrus, English: High Cathedral of St. Peter) is a Roman Catholic church in Cologne, Germany. It is the seat of the Archbishop of Cologne and the administration of the Archdiocese of Cologne. It is a renowned monument of German Catholicism and Gothic architecture and is a World Heritage Site. It is Germany's most visited landmark, attracting an average of 20,000 people a day. (Source: Wikipedia).