As an etching of St. Peter's Basiilica, Pianesi's second view of the Piazza Navona depicts contemporary Rome, referencing its ancient foundations in the title inscription. By using his now finely honed printmaking techniques and elements of theatrical composition, Piranesi creates a dynamic scene and an illusion of profound depth in space. He has employed an extremely wide range of blacks and grays, emphasizing points of shadow and sunlight and constructing atmospheric perspective as the long piazza recedes into the distance. The Fontana del Moro abuts against the frame closest to the viewer and seems enveloped in a shadow cast by an unseen building to the right. The dark blacks that articulate this fountain, the hatching at the right, and the shadow on the Pamphili Palace at the left present a sharp contrast to the delicate grays at the vanishing point. By then pushing this point of convergence to the right, a characteristic of his compositions, Piranesi permits an uninterrupted view of the piazza's monuments including Borromini's church of Sant'Angese, the Fontana dei Quattro Fiumi, and the Fonatana del Nettuno.

from Sullo, The World of Piranesi: A Multidisciplinary Approach to Learning beyond the Classroom through Italian Language and Culture (Notre Dame, 2010)