The Catacombs of San Callisto are just one of the many catacombs of Rome, five of which are regularly open to the public. These Catacombs were used by Christians as subterranean burial places.

Built in around 150 AD, the Catacombs of San Callisto span five floors and hold over half a million bodies, making them the largest of their kind in Rome. Whilst some believe that the practice of underground burials derived from the persecution of the Christians and thus the need to keep the graves safe, others think that this was just the custom at the time and due to the fact that they owned little land.

The most famous residents of the Catacombs of San Callisto are a number of popes of the third century, but not Pope St. Callixtus after whom the catacombs are named. Instead, this pope was responsible for part of the construction and expansion of the Catacombs of San Callisto.