There's something spooky yet compelling about seeing resting places of the dead. If this sounds interesting to you, stop by Catacombs of St. Callixtus.
This tomb site is often on the itineraries of travelers to Appio Latino. But Catacombs of St. Callixtus isn't the area's only highlight. St. Peter's Basilica, Roman Forum, and Piazza Navona are some other worthwhile sights nearby.