Aachen Cathedral (Aachener Dom)

Aachen Cathedral began as the Palatine Chapel of Emperor Charlemagne, built between 793 and 813 AD as the centrepiece of his imperial residence in what is now North Rhine-Westphalia. The octagonal core, modelled on Byzantine churches such as San Vitale in Ravenna, is the oldest standing part of the building and one of the few surviving structures from the Carolingian era anywhere in Europe. Charlemagne was buried in the chapel in 814, and from 936 to 1531 it hosted the coronations of 30 German kings, cementing its role at the centre of medieval imperial authority. Gothic additions, including the soaring choir hall completed in 1414, were built to accommodate the growing crowds of pilgrims and to house an expanding collection of relics and treasures. Inside, visitors find Charlemagne's marble throne set on a raised platform in the upper gallery, the golden Shrine of Charlemagne containing his remains, and the bejewelled Shrine of the Virgin Mary. The Cathedral Treasury, housed in a separate building, displays the Lothar Cross, the bust reliquary of Charlemagne, and other Carolingian and Ottonian goldsmith work considered among the finest north of the Alps. Restoration campaigns through the 19th and 20th centuries stabilised the structure and recovered original Byzantine-style mosaics in the dome, and the cathedral survived Allied bombing in the Second World War with its core intact, though repairs continued for decades afterward. The building today functions as an active parish church and bishop's seat while remaining open to visitors, with the octagon, choir hall, and treasury together forming a chronological record of German ecclesiastical architecture spanning more than a thousand years.