We bought something for someone back home, then headed to one of the civic attractions, as mentioned in all guide-books and web sites: the walk along the old city walls.
Unfortunately, a large part is closed on weekdays, so the 3 euros apiece didn't buy us much. My recommendation is to skip it and head for the Cathedral.
For a bit more (3,80) per person, we got to immerse ourselves in art and religion spanning 1200-1800, and the free audio guides were very good, if a little too detailed at times. Great stuff, especially the amazing cloister, with its ingenious, varied carvings
By then, we were ready for lunch, and found the right place, downhill from the cathedral. It was a teeny bistro called 'La Teulas' and they did right by us.
For the first course, we both had huevos del plato, a casserole with two eggs, chorizo and tomatoes, baked and served bubbling, with bread.
Second course: Karen had a slab of grilled beef with herbed potatoes and I had a delicious creamy rissoto, with red peppers and other subtle additions