(three front and two rear) in Istrian stone, built in a round arch. Ponte di San Pietro (Saint Peter's bridge), built in the 17th century, marks the beginning of the most antique and characteristic district of Comacchio. It has been completely restored in the recent days. Ponte dei Sisti, built in the 18th century entirely with brick, with a single arch. Ponte degli Sbirri or Ponte delle Carceri ("Bridge of the cops" or "Bridge of the prisons"), built between 1631 and 1635 and designed by Luca Danese of Ravenna by the will of cardinal Giovan Battista Pallotta, it consists of three arches in brick and Istrian stone. It takes its name from the facing district prison, which once housed the prisoners of Comacchio, mostly poachers or "fiocinini". This bridge constitutes the main canal junction of the city, from which it was possible to sail towards the sea in all directions. The San Pietro district extends southwards from here. Ponte del Teatro (Theatre's bridge), built in the 17th century. Ponte del Carmine and Ponte Pizzetti, respectively located to the side and in frieze of Chiesa del Carmine, are among the largest in the city—although not the most complex, having a single arch. Both date back to the 18th century; Pizzetti Bridge was recently fully restored. Buildings Torre civica, or the clock tower, is a reconstruction of the 19th of the original one, dated back to the 14th century, which ruined to the ground in 1816. Since 1872 the tower has been equipped with a mechanical watch. Palazzo Bellini is an aristocratic palace built between 1868 and 1870. Today it hosts the Gallery of Contemporary Art, the historical archive, the town's library and offices of the department of cultural institutions. Palazzo Patrignani, dating back to the 16th century and restored several times, was inhabited by an eminent family of Comacchio. Findings of an ancient flooring testifies that probably it had been the seat of the old convent of Church of San Nicolò. Today it hosts university courses. The antique Ospedale degli Infermi is a neoclassical architecture built between 1778 and 1784 by the will of Pope Clement XIV. The project was assigned to the Venetian architect Antonio Foschini, who designed the facade and the main body of the building. The back was built by the Ferrarese architect Gaetano Genta, who replaced Foschini in 1780 in the works supervision and completed the building.