Kölner Dom’s twin spires crown a vast Gothic nave begun in 1248 and completed in the 19th century. Volcanic tuff and sandstone weather under pollution and rain, requiring a permanent works yard. The shrine of the Three Kings, stained glass, and vaults demand conservation while millions pass through each year.
Medieval building campaigns paused for centuries; 19th‑century Prussian completion followed medieval plans, unifying elevations and towers.
Soft tuff and harder sandstones age differently; blocks are replaced, joints repointed, and iron monitored. Stained glass receives protective glazing and cleaning.
Scaffolding is a constant; workshops carve replacement elements. Safety and routing manage railway‑adjacent crowds at the square.
Climb the tower if fit; check the treasury and modern stained glass by Richter.
