I missed this on my first trip to Rome. It is an ancient Roman marble mask. It’s called the Mouth of Truth because according the the medieval legend, it will bite off the hand of anyone who lies. It is over 2,000 years old. People who were accused of perjury or adultery would put their hand into the mouth after swearing under oath. So, if you are trying to determine if someone is lying to you, just plan that trip to Rome and have them stick their hand in the Bocca Della Verità.
The Bocca Della Verità dates back to the 1st century AD.
Located at the Santa Maria in Cosmedin church, at the Piazza della Bocca Della Verità.
Quick Trip Girl 