This is a nice old square faceing an old Palace (now the French Embasy). It was built by the Farnese , a rich family in the Renaissance with Michealangelo involved (according to Google). It's located just behind Campo de' Fiori.
My Favorite feature are the two big Bathtub fountains in front. I've read one of the Farnese became a Pope and helped his family get these from a Roman era Bathhouse. read more