Aachen Cathedral

The Aachen Cathedral's octagonal core, built around 800 under Charlemagne, is among the best-preserved Carolingian churches in Europe and in 1978 became Germany's first UNESCO World Heritage Site. Its design drew directly from Byzantine centralized structures — ancient columns and spolia were transported from Ravenna and Rome specifically to give the building imperial authority. Between 936 and 1531, thirty German kings were crowned here on Charlemagne's throne, a dynastic continuity unmatched anywhere in the Holy Roman Empire. The 14th-century Gothic choir houses the Karlsschrein, an early 13th-century gilded reliquary containing the remains of Charlemagne himself. The cathedral remains an active pilgrimage site: the Heiligtumsfahrt, held every seven years, draws hundreds of thousands of pilgrims from across Europe.