Opposite the Doge’s Palace, beyond the rio (a small canal) crossed by the Bridge of Sighs, the Palazzo delle Prigioni is one of the first buildings in Europe put up expressly to serve as a prison: a severe, single-storey classical façade, with a portico and mighty rusticated blocks of Istrian stone, begun in 1563 by Rusconi, resumed by Antonio da Ponte in 1589 and completed by the Contino in 1614.