The neo-classical Our Lady of Mercy Cathedral faces the Plaza de Armas across the city's main square. The first church on this site went up in 1648; the present cathedral, designed by French architect Jean Herbage, was finished in 1844 and is the seat of the Archdiocese of La Serena.
Three nave aisles, stone-coloured walls, and a calm interior. The Museum of Religious Art at the back of the nave displays vestments, gilt processional staffs, and 17th-century paintings from the order's Bolivian missions.