Mezquita, Córdoba

The alternating red and white voussoirs, constructed on site between 784 and 987, create an optical rhythm that has inspired architects for centuries. Compared to the average cathedral's stone vaulting, this hypostyle hall achieves a 40% lighter visual mass through its 72 superimposed arches. The original mihrab, faced in 1,000 kilograms of Byzantine gold mosaic, remains a pilgrimage highlight.