Bocca della Verità

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.

• http://en.wikipedia.org/wiki/Bocca della Verità