4 Best Sights in Piazza Navona, Campo de' Fiori, and the Jewish Ghetto, Rome

The fourth component of the magnificent collections of the Museo Nazionale Romano, this museum is unusual because it represents several periods of Roman history. The crypt is part of the Balbus Theater complex (13 BC), and other parts of the complex are from the medieval period, up through the 20th century. Though the interior lacks the lingering opulence of some other Roman sites, its evolution via continuous use over centuries offers a unique archaeological glimpse at how the city transformed. Note that recent restoration works have resulted in closures here; check for updates before visiting.

Looming over the Jewish Ghetto, this huge portico, with a few surviving columns, is one of the area's most picturesque set pieces, with the church of Sant'Angelo in Pescheria built right into its ruins. Named by Augustus in honor of his sister Octavia, it was originally 390 feet wide and 433 feet long; encompassed two temples, a meeting hall decorated with bronze statues, and a library; and served as a kind of grandiose entrance foyer for the adjacent Teatro di Marcello.

In the Middle Ages, the cool marble ruins of the portico became Rome's pescheria (fish market). A stone plaque on a pillar (it's a copy as the original is in the Musei Capitolini) states in Latin that the head of any fish surpassing the length of the plaque was to be cut off "up to the first fin" and given to the city fathers or else the vendor was to pay a fine of 10 gold florins. The heads, which were used to make fish soup, were considered a great delicacy.

One of the most important archaeological areas in Rome was only discovered in 1926 when construction around Teatro Argentina unearthed four Republican-age temples. The so-called Sacred Area was closed to the public for decades and was happily colonized by cats, who still roam the ruins. But now, a series of walkways allows up-close visits to the site, along with a small but smart collection of antiquities. The exact history of the temples is still being studied, but it is thought that the most ancient of the four (built in the 4th century BC) was dedicated to Feronia, a fertility goddess. While scholars continue to debate the origins of some of the temples here, they do agree that the large tuffa foundation behind the round temple was the Curia of Pompey, where senate sessions were once held—and the spot on which Julius Caesar was assassinated on the Ides of March (March 15) of 44 BC. 

Begun by Julius Caesar and completed by the emperor Augustus in 13 BC, this theater could house around 14,000 spectators. Like other ancient monuments, it was transformed into a fortress during the Middle Ages. During the Renaissance, it was converted into a residence by the Savelli, one of the city's noble families. Today, only the archaeological park around the theater is open to the public, with its picturesque walkway that curves past the ruins and links to the Portico d'Ottavia. In summer, the small park becomes a magical venue for open-air classical music concerts.