Bocca Della Veritá (Mouth of Truth): This large, round face carved on a flat piece of marble is located in Santa Maria in Cosmedin. Tourists queue up to place their hand in the mouth of the sculpture, following the legend that, should they tell a lie while their hand is in place, the face will bite them. There are two theories regarding the origin of the carving. One is that it is an ancient drain cover, and the other is that it was once part of a fountain.