Ancient Roman recycling at its finest. Originally, this spot held the largest of Rome’s hedonistic baths (dating back to a.d. 298 at the time of the reign of Emperor Diocletian). During the Renaissance, a church, a vast cloister, and a convent were built around and into the ruins—much of it designed by Michelangelo, no less. Today the entire complex is part of the Museo Nazionale Romano, and this juxtaposition of Christianity, pagan ancient ruins, and exhibit space make for a compelling museum stop that’s usually quieter than the city’s usual blockbusters. There’s a large collection of inscriptions and other stone carvings from the Roman and pre-Roman periods, alongside statuary. Only Aula 10 conserves trace of the vast baths, which accommodated 3,000 at a time when they opened in the early 4th century. They were abandoned in the 6th century, when invading Goth armies destroyed the city’s aqueducts.

Note: The museum is undergoing restoration, and only sections may be open.