Catacombe di San Callisto

Stretching for kilometers underground along the ancient Via Appia, the Catacombs of San Callisto were the official cemetery of the early Church in Rome and became the burial site of numerous popes and martyrs in the 3rd century. Guided tours, which are required rather than optional, lead through a fraction of the tunnels, explaining the burial customs and symbolism of early Christianity along the way. The cool, quiet underground setting, reached via a short trip outside the city center, gives a genuinely different atmosphere from Rome's above-ground sights. It's a strong choice for visitors interested in the roots of Christianity in Rome rather than imperial history.