Aachener Dom (Aachen Cathedral), Aachen (must see)

Aachen Cathedral, also known as the Imperial Cathedral, was built in the late 8th century on the orders of Charlemagne. It is one of the oldest cathedrals in Europe and became the first German site added to the UNESCO World Heritage list in 1978. From the start, the building was meant to express political authority as well as religious power.

At the center of the complex is the Palatine Chapel, completed around 805. Its octagonal plan reflects strong Byzantine influence, especially the church of San Vitale in Ravenna. The number eight had Christian meaning, linked to resurrection and renewal. The design also follows strict proportions: both the dome height and the diameter measure 100 Carolingian feet. In medieval thinking, multiples of ten symbolized order and completeness, reinforcing the chapel’s role as a sacred and carefully planned space.

After Charlemagne’s death, the chapel became his burial place. Over time, the cathedral gained major political importance. Between 936 and 1531, 31 German kings and 12 queens were crowned here, making it a central stage for imperial ceremony in the Holy Roman Empire.

The cathedral’s Treasury is one of the most important church treasuries in Europe. Its objects include the Throne of Charlemagne, the four large Aachen relics-among them a cloth linked by tradition to the Virgin Mary-and the Pala d’Oro, a gold altar screen decorated with detailed metalwork.

The building did not remain unchanged. Later centuries added new structures around the original chapel. The most striking addition is the Gothic choir hall from the 13th century, built with tall walls and large stained-glass windows. Its height and light contrast clearly with the solid, compact form of the Carolingian core, showing how the cathedral reflects many phases of European history within a single structure.