The Colegiata de Santa Juliana is the finest Romanesque church in Cantabria, built mainly in the 12th century on the site of an earlier monastery that housed the relics of the town's patron saint. The south facade and the three apses are magnificent examples of the style, with blind arcading, corbelled friezes, and carved decorative motifs that show real ambition for a relatively remote settlement. The tower is a later Gothic addition but blends comfortably with the earlier fabric.
The cloister is the highlight. Its carved capitals represent one of the most complete Romanesque sculptural programmes in northern Spain: biblical scenes, mythological beasts, geometric patterns, and human figures, all rendered with enormous vitality. The workmanship ranges from rough to exquisite, suggesting multiple hands over several decades. The church is open daily to visitors; there is a small admission charge that helps with ongoing conservation work.