Santa Maria in Cosmedin, Piazza della Bocca della Verità, Rome.

(Fondazione Teatro Dell Opera di Roma to left and) the Basilica of Saint Mary in Cosmedin (Italian: Basilica di Santa Maria in Cosmedin or de Schola Graeca) is a minor basilica church in Rome, Italy. It is located in the rione of Ripa.
The church was built in the 8th century during the Byzantine Papacy over the remains of the Templum Herculis Pompeiani in the Forum Boarium and of the Statio annonae, one of the food distribution centres of ancient Rome (another is to be found at the Theatre of Balbus). A deaconry was a place where charity distributions were given to the poor, and it looks likely that such an institution would have been built near the Roman annona.
Since it was located near many Byzantine structures, in 7th century this church was called de Schola Graeca, and a close street is still called della Greca. Greek monks escaping iconoclastic persecutions decorated the church around 782, when pope Adrian I promoted its reconstruction; the church was built with a nave and two aisles and a portico. Because of its beauty, the church received the adjective cosmedin (from Greek kosmidion), ornate. A sacristy and an oratory dedicated to St. Nicholas were added in the 9th century, by order of Pope Nicholas I, who also built a papal residence, but they were destroyed in the Sack of Rome (1084) by Robert Guiscard's Norman troops.

La Bocca della Verità (English: the Mouth of Truth) is an image, carved from Pavonazzo marble, of a man-like face, located in the portico of the church of Santa Maria in Cosmedin in Rome, Italy. The sculpture is thought to be part of a first-century ancient Roman fountain, or perhaps a manhole cover, portraying one of several possible pagan gods, probably Oceanus. Most Romans believe that the 'Bocca' represents the ancient god of the river Tiber.
The most famous characteristic of the Mouth, however, is its role as a lie detector. Starting from the Middle Ages, it was believed that if one told a lie with one's hand in the mouth of the sculpture, it would be bitten off. There was also a medieval legend, wrongly believed to originate with the Roman poet Virgil, of an adulterous empress who managed to deceive her husband in a trial using the Mouth. This is an infrequent subject in medieval and Renaissance art, forming part of the Power of Women literary topos. The piece was placed in the portico of the Santa Maria in Cosmedin in the 17th century. The Mouth of Truth is known to English-speaking audiences mostly from its appearance in the 1953 film Roman Holiday. The film also uses the Mouth of Truth as a storytelling device since both Hepburn's and Peck's characters are not initially truthful with each other.

more on https://en.wikipedia.org/wiki/Santa_Maria_in_Cosmedin , https://en.wikipedia.org/wiki/Bocca_della_Verità