The large Piazza del Duomo is connected near to other famous buildings , for example the Palazzo del Comune and the Palazzo del PodestÃ . In July , the Giostra dell ` Orso ( `` Bear Joust '' ) takes place in the square . The large Piazza del Duomo is lined with attractive original buildings as the Palazzo del Comune and the Palazzo del PodestÃ : it is the setting ( in July ) of the Giostra dell ` Orso ( `` Bear Joust '' ) , when the best horsemen of the districts of the town tilt with lances at a target held up by a dummy shaped like a bear .