Fodor's Expert Review Catacombe di San Sebastiano

The 4th-century church at this site was named after the saint who was buried in its catacomb, which burrows underground on four different levels. This was the only early Christian cemetery to remain accessible during the Middle Ages, and it was from here that the term "catacomb" is derived—it's in a spot where the road dips into a hollow, known to the Romans as a catacumba (Greek for "near the hollow").