The Concattedrale di Santa Maria Assunta sits on the main piazza of the upper town, its broad Baroque facade out of proportion with the square in front of it. The current building dates from the late seventeenth century, but the site has been a place of worship since at least the eighth century, and fragments of earlier structures survive in the crypt.
Inside, the single nave is lined with side chapels, several of which preserve panels and frescoes salvaged from earlier churches in town. The cathedral treasury — opened on request — holds a fourteenth-century processional cross that the town carries through the streets during Holy Week, in a procession that has not changed materially in six hundred years.