St. Callixtus became the official cemetery of the Church of Rome in the early 3rd century. Its best-known chamber is the Crypt of the Popes, nicknamed the little Vatican by archaeologist Giovanni Battista de Rossi after he rediscovered it in 1854. Nine 3rd-century popes were buried there.

• What you'll see: The Crypt of the Popes; the Crypt of St. Cecilia, whose remains stayed here until 821; and the Cubicles of the Sacraments, with some of the oldest paintings preserved in the catacombs.
  
• Scale: Nearly 20km of galleries across several levels, making it one of Rome's largest catacomb complexes.
  
• Location: Via Appia Antica 110 | ATAC buses 118 and 218.
  
• Closed: Wednesdays.
  
• Best for: First-time visitors who want the strongest introduction to papal and early-Christian Rome.
  
• Recommended tours: St. Callixtus Guided Tour, Guided Tour with Transfers

Domitilla developed into what the Pontifical Commission describes as Rome's largest underground Christian cemetery. Its standout feature is the semi-underground Basilica of Saints Nereus and Achilleus, a three-nave church built at the end of the 4th century above the martyrs' burial place.

• What you'll see: The Basilica of Saints Nereus and Achilleus; the Flavian Hypogeum, which began as a private pagan burial space; and early Christian frescoes and burial chambers.
  
• Scale: Around 17km of galleries arranged across four levels.
  
• Location: Via delle Sette Chiese 282, in the Via Ardeatina area south of central Rome.
  
• Closed: Tuesdays.
  
• Best for: Visitors who want a larger site with more architectural variety than rows of burial galleries alone.
  
• Recommended tours: Domitilla Guided Tour, Guided Tour with Transfers

St. Sebastian layers several chapters of Roman history into one complex. Beneath the Christian cemetery lie three richly decorated Roman mausoleums from the 2nd century. By the 3rd century, the site was associated with the veneration of Peter and Paul, and the Triclia still preserves hundreds of pilgrims’ graffiti invoking the apostles. Christian tradition holds that their relics were temporarily venerated here.

It is also from the ancient name of this area, ad catacumbas, that we get the word catacomb.

• Look out for: The Triclia, where pilgrims left hundreds of invocations to Peter and Paul; three richly decorated Roman mausoleums; and the Crypt of St. Sebastian.
  
• Scale: Around 12km of galleries across three levels, with only a portion open on the guided route.
  
• Location: Via Appia Antica 136 | About 500m from St. Callixtus.
  
• Closed: Mondays.
  
• Best for: Visitors who want Roman, pagan and early-Christian history in the same visit rather than a purely Christian cemetery.
  
• Recommended tours: St. Sebastian Guided Tour, Guided Tour with Transfers

Priscilla's reason to visit is different: come here for the art. Known as the Queen of the Catacombs, the cemetery preserves some of Rome's most important early Christian paintings, including an image of the Virgin and Child dated to around 230–240 that the Pontifical Commission describes as the oldest known image of the Mother of God in the West.

• What you'll see: The Greek Chapel and its 3rd-century paintings; the Cubicle of the Veiled Woman; and the Virgin and Child with a prophet, usually identified as Balaam.
  
• Scale: More than 13km of tunnels across two levels.
  
• Location: Via Salaria 430 | buses 63, 92 and 310; or Metro B1 to S. Agnese/Annibaliano followed by about a 15-minute walk.
  
• Closed: Mondays.
  
• Best for: Art and archaeology lovers who want frescoes and early Christian iconography rather than the biggest underground complex.
  
• Recommended tours: Priscilla Guided Tour

St. Agnes feels different because the visit revolves around one figure. The cemetery developed around the tomb of Agnes, a young Roman martyr whose cult became one of the most important in early Christian Rome. The underground cemetery is arranged across three levels beneath the complex on Via Nomentana.

• What you'll see: Underground galleries associated with the burial of St. Agnes, along with inscriptions, graffiti and funerary objects recovered from the cemetery.
  
• Pair it with: The Basilica of Sant'Agnese fuori le Mura above and the nearby Mausoleum of Santa Costanza, celebrated for its 4th-century mosaics.
  
• Scale: A three-level catacomb complex rather than the sprawling 17–20km networks of Callixtus and Domitilla.
  
• Location: Via Nomentana 349, north-east of Rome's historic centre.
  
• Best for: Visitors who want a more focused visit built around one saint, with worthwhile sights above ground too.
  
• Recommended tours: St. Agnes Guided Tour

• Catacombs of St. Callixtus: 9am–12pm; 2pm–5pm (Thu to Tue)
  
• Catacombs of Domitilla: 9am–12pm; 2pm–5pm (Wed to Mon)
  
• Catacombs of St. Sebastian: 9:15 am–5:15 pm
  
• Catacombs of Priscilla: 9am–12pm; 2pm–5pm (Tue to Sun)
  
• Catacombs of Sant’Agnese: 10am–1pm; 3pm–6pm

Closed on

• Catacombs of St. Callixtus: Wednesdays
  
• Catacombs of Domitilla: Tuesdays
  
• Catacombs of Priscilla: Mondays
  
• Catacombs of Sant’Agnese: December 25, January 1, Easter, the morning of religious holidays

Best time to visit: Early mornings or late evenings.