The fountain of the Mascherone (Mask) that gave the name to the street just opposite, was originally isolated. Today it leans against a wall built in the past century. The mask probably dates back to the Roman age and was adapted in the seventeenth century for use as a fountain and is decorated on two sides by volutes. Its upper part is framed by an architrave with in the centre an iron-wrought lily, coat of arms of the Farnese family (or of France) that replaced a stone lily in the past century. The Acqua Paola that pours from the mask flows into the small basin below and then flows down into the large rectangular granite pond that is probably ancient, and lastly into the pool at the ground level, delimited by two small columns connected with iron bars. On the occasion of feasts by the Farnese family, the fountain poured wine instead of water. In 1720 the fountain poured wine for three days in a row to honour the appointment of Marco Antonio Zondadori to Grand Master of the Order of Malta.