Cathedral of the Savior (La Seo)
La Seo is Zaragoza's oldest church and an architectural masterpiece combining Romanesque, Gothic, Mudéjar, and Baroque styles. Built on the site of a Roman forum and later a mosque, it houses a stunning Tapestry Museum with Flemish tapestries from the 15th to 18th centuries. It's part of the UNESCO World Heritage Site of Mudéjar Architecture of Aragon.