Dominating the eastern end of Plaza del Pilar, La Seo is Zaragoza's finest work of Christian architecture, built between the 12th and 17th centuries and displaying a fabulous spread of styles from Romanesque to baroque. It stands on the site of Islamic Zaragoza's main mosque (which itself stood upon the temple of the Roman forum). The admission price includes La Seo's Museo de Tapices, a collection of Flemish and French tapestries considered the best of its kind in the world.
The cathedral's northeast external wall is a Mudéjar masterpiece, deploying classic brickwork and colourful ceramic decoration in complex geometric patterns. Inside, beautiful fan vaulting adorns the ceiling while the chapels, framed by encrusted stonework, ring the changes from the eerie solemnity of the Capilla de San Marcos to the golden baroque baldachin of the Capilla del Santo Cristo. The exquisite 15th-century alabaster high altarpiece is well worth scrutiny too.