The west facade is divided into five levels. The most eye catching stylistic element is a huge round window, surrounded by eight small rosettes, which forms a clear centre of the west facade. The rosette symbolises the four Evangelists. Despite the symmetry of the twin towers, there is rich variation in forms and building elements, e.g. round and pointed arches, pilaster strips, small pillars, archivolts, windows and blind arches. The upper level of the north tower includes Gothic elements (e.g. window tracery).