This branch of the National Museum of Rome houses the archaeological remains of the vast portico belonging to the 1st-century-b.c. Theatre of Lucius Cornelius Balbus, discovered here in 1981. The ground floor’s exhibits chronicle the history of the site through to the medieval period and the construction of the Conservatorio di Santa Caterina della Rosa. The second floor (“Rome from Antiquity to the Middle Ages”) explores the transformation of the city between the 5th and 9th centuries, using thousands of ceramic objects, coins, lead seals, bone and ivory implements, precious stones, and tools found on the site. The museum helps decode the complex layers under Rome’s streets, but given its comprehensive collections, it’s recommended for history and archaeology buffs.