Yes, I am still concentrating on the Cathedral, better known as “Aachener Dom”, the first building to make the Unesco-list in Germany. The Dom shows how something grows and changes with time passing, but without losing its beauty and purpose.
Charlemagne was determined to make Aachen the center of his empire around 790, because the hot springs in Aachen were especially soothing during the cold winter month. So when he decided to mostly stay there in winter, it was obvious to the religious king that he needed to build the most beautiful church north of the alps there. Well, you may say there are so many beautiful churchs in Europe these days, but there were not 1200 years ago. The king planned and constructed the original church as an octagon, which symbols divine perfection.