The city's main monuments occupy the four sides of the piazza: the college of the Jesuits; the Palazzo Comunale (formerly the Palazzo Apostolico), designed by Bramante, that houses an art gallery with works of Lorenzo Lotto, Vouet and Annibale Carracci as well as a collection of maiolica, and the Shrine of the Holy House (Santuario della Santa Casa). It also boasts a massive line of walls, designed by the architect (and military engineer) Antonio da Sangallo the Younger, which were erected from 1518 and reinforced in the 17th century.