For some history...the papacy did not want the Jewish religion to assimilate with the Catholic population, so in 1555 the Romans built a wall around a four block (or .01 square mile) area near the Campo de' Fiori and along side the Tiber River. The cost of construction had to be paid by the Jewish community!! Each night 2,000+ Jews had to return to within the walled area and its gates were locked over night.
Laws governing Jews were very harsh. Professions were restricted (ragmen, second-hand dealers, fish mongers, and pawnbrokers). Jews were required to attend Catholic religious services on the Jewish sabbath. It is said that they put rocks in their ears to block out the sounds of the Christian services and singing. There were many other atrocities.
With few brief exceptions, depending on who was in power in Rome, the ghetto and its restrictions were controlled by the papacy and in force until 1870. At that time the Kingdom of Italy was established and the papacy states and the walled ghetto were dissolved.
This neighborhood has such a fascinating history that this commentary hardly scratches the surface. But you can find tons of info on the Internet under "Roman Jewish ghetto." Wikipedia is a good place to start at: https://en.wikipedia.org/wiki/Roman_Ghetto. I will have to read more at home.
We would criss-crossed this area a number of times while in Rome. And we would have lunch in a fabulous Jewish restaurant later.
From the Campo de' Fiore we continued down the cobblestone streets made of squares of basalt. In the Roman ghetto district, we saw many bronze plates embedded in streets and walls listing names of those that had been murdered or missing during the German occupation. This seemed a touching gesture to assure those individuals would be remembered throughout time.
At the north end of the quarter is the Piazza Mattei where we found a whimsical sculpture. It is the Fontana delle Tartarughe (Fountain of the Turtles). It was designed in the 1580s by Giacomo della Porta. It too has gone through several iterations (dolphins changed to turtles, etc.)
Here is some interesting architecture and roof top gardens in the area.
Mike, car buff that he is, loved this Fiat (nicknamed "Fix It Again Tony") 500. The first of this model was manufactured in 1957. This beat up convertible version had to be from around that time. We read that you can rent a restored vintage model for $290 a day!!