Though this is one of Rome's oldest churches, with a haunting, almost exotic interior, it plays second fiddle to the renowned artifact installed in the church portico, on the left as you enter. The Bocca della Verità (Mouth of Truth) is in reality nothing more than an ancient drain cover, unearthed during the Middle Ages. Legend has it, however, that the teeth will clamp down on a liar's hand, and to tell a lie with your hand in the fearsome mouth is to risk losing it. Hordes of tourists line up to take the test every day, cameras in hand to bring the proof to the folks back home.

Few churches, inside or out, are as picturesque as this one. The church was built in the 6th century for the city's burgeoning Greek population. Heavily restored at the end of the 19th century, it has the typical basilica form, but it also has an altar screen, an element characteristic of Eastern churches. It stands across from the Piazza della Bocca della Verità, originally the location of the Forum Boarium, ancient Rome's cattle market, and later the site of public executions.