This fifth century church is famous for housing Michelangelo's recently restored and seminal sculpture of Moses. The church also contains chains that, according to tradition, bound the Apostle Peter during his imprisonment in the Mamertine jail. BUS: 74, 85. METRO: Cavour

While this fourth-century church has enjoyed several decorative additions over the years, its original shape is still intact, making this Rome's only basilica with such a distinction.

Built in 1280, this is Rome's lone Gothic church. The building underwent extensive architectural modifications in the 19th century and is unique even in Rome. BUS: 64, 70, 81, 87, 119, 492 or 628. TRAM: 8.

Historical evidence for the Roman persecution that marked much of early Christianity, as this crypt is the burial site for numerous Christian martyrs. The catacombs are also an inspirational reminder of how Christianity has flourished in light of such a tumultuous beginning. The catacombs hail from the second century and were built outside the city, for Roman laws forbid burial within the precincts.

The crypt is one of the most interesting you'll ever see because the four chapels and their Baroque decor consist of the bones of 4000 friars. Yes - the walls, ceilings and chandeliers are decorated with skulls, bones and full skeletons. Work first began on the site in 1528 and was eventually completed in 1870. Not for the faint of heart. BUS: 52, 63, 116, 150 or 630. METRO: Barberini