The highlight of the old town is the fortress-like Catedral de Santa Maria. Begun in the 12th century, it reflects a stoic Romanesque style in most of its construction, though the ornate main portal is reckoned the earliest work of Gothic sculpture on the Iberian Peninsula. Admission covers the lovely Gothic cloister and its viewpoints, plus the main nave and chapels.
Guided visits to the cathedral roof and tower (€8) start at noon and 1pm, Monday to Friday, July to September.