Piazza della Rotonda, also known as Piazza del Pantheon, dominated by the presence of the Pantheon, the toponym derives from the popular name given by the Romans to the great monument that has come intact from ancient Rome: the Rotonna. In the center of the square is a Renaissance fountain designed around 1575 by Giacomo Della Porta, in the place that since the time of Pope Eugene IV (first half of the 15th century) was occupied by a porphyry basin and two stone lions. In the 18th century the fountain was modified from a design by Filippo Barigioni and surmounted by the so-called “obelisk macuteo”, a small monolith from the time of Ramses II found in the 14th century in Piazza San Macuto. The square was used until 1847, despite the repeated prohibitions of the papal authorities, as a fish and vegetable market. (wiki)