At Castelletto you may admire the church of St. Zen, a small Romanesque masterpiece with interesting frescoes. Of the same period is the tiny church of St. Anthony in Biasa. There are very beautiful frescoes in the church of San Nicola in the little square of Assenza.
At Castelletto you will also find the main convent of the Little Nuns of the Sacred Family, the religious congregation founded by Don Giuseppe Nascimbeni, beatified by Pope John Paul II. The parochial church of Castello conserves an image of the Madonna that many believe to have miraculous powers.