The Cathedral of El Salvador sits in the centre of the upper town, a 16th-century replacement for an earlier Gothic church. It is small by Spanish cathedral standards but exceptionally rich inside: a series of finely carved walnut altarpieces, a remarkable collection of Flemish tapestries depicting the life of Gideon, and a small museum displaying the cathedral treasure — silver work, vestments, illuminated manuscripts.
Entry is by guided tour only (about 40 minutes, Spanish-language); buy tickets at the diocesan museum next door. The tour is the best way to access the otherwise locked Plaza Mayor side of the building and to see the chapter house behind the high altar.