Mouth of Truth (Bocca della Verità)

An ancient marble mask — likely a 1st-century drain cover from a temple — set into the portico wall of Santa Maria in Cosmedin. Medieval legend held that it would bite off the hand of any liar who placed it inside, a tradition immortalized when Gregory Peck pretended to lose his hand for Audrey Hepburn in Roman Holiday (1953). It's a quick photo stop, free with a small donation, and the Romanesque church behind it is worth a brief look.