The wall layout of the Cologne Cathedral follows a classic three-tier arrangement: large pointed arcade arches at the base, a delicate, stone-carved triforium gallery in the middle, and towering clerestory windows that flood the upper vaults with filtered light. Slender, clustered stone shafts rise seamlessly from the floor to meet the elegant quadripartite ribbed vaults, structurally distributing the roof's weight outward to exterior flying buttresses. This massive, unified skeleton allows the walls to be filled with extensive cycles of masterfully crafted stained glass instead of solid stone.