Piazza del Popolo was designed to provide a scenic entrance to Rome for the countless visitors who arrived from the north, along theVia Flaminia.
The Porta del Popolo stands roughly on the same site as the ancient Porta Flaminia. The outer face was designed by Nanni di Baccio Bigio (c. 1512-68), while the inner face is the work of Gian Lorenzo Bernini (1598-1680). Just inside the gate stands the church of Santa Maria del Popolo. In the centre of the piazza is an ancient Egyptian obelisk, which once graced the spina of the Circus Maximus.
The layout of the piazza was transformed by the Roman architect Giuseppe Valadier (1762-1839), at the behest of Pope Pius VII (r. 1800-23). Valadier designed the two hemicycles, which give the piazza its pleasing symmetry. The focal point of each hemicycle is a grand fountain; on the west side is the Fontana del Nettuno (Fountain of Neptune) and on the east the Fontana del Dea Roma (Fountain of the Goddess Roma, both the work of the Roman sculptor Giovanni Ceccarini (1790-1861). At either end of each hemicycle stand statues depicting the four seasons. Valadier also added the four fountains at the base of the obelisk.
A plaque on the north side of the piazza records the intervention of Pope Pius VII. It reads: PIVS · VII · PONT · MAX · / FORI · AREAM / PER · HEMYCICLOS · PORREXIT / ET · GEMINO · FONTE · EXORNAVIT / VT · AEDIFICIIS · BINIS · VTRIMQVE / VNA · PARITER · EXSTRVCTIS / PRINCIPEM · VRBIS · ADITVM / NOVO · CVLTV · NOBILITARET / PONT · ANNO · XXIV (Pius VII Pontifex Maximus extended the confines of the piazza with hemicycles and embellished it with twin fountains in order that by the two buildings constructed uniformly on each side he might ennoble with new refinement the city's chief approach in the 24th year of his pontificate).