A musical experience
Attending an organ concert is one of the obligatory cultural experiences of the city. This event sells out quickly and is quite a sight to see, as the organ of the cathedral is huge and there are very good acoustics.
They say it is one of the largest in Europe. Admission is about 35 €, depends on where you're going to be sitting, and although it's very good for music lovers, but perhaps not if they only play the organ, because it becomes too overbearing.