This old Cistercian abbey, also known as the Bergischer Dom (the cathedral of the duchy of Berg), is situated in a valley in the Berg region, an area very popular with the inhabitants of Cologne. Since 1857, both Protestant and Catholic services have been held in this Gothic-style church. Note the grisaille stained-glass windows in the chancel and the huge coloured glass window (18m by 8m) dating from 1400 above the west door.