Underground Rome: what you can visit beneath the city

Underground Rome is not a place: it is a second layer of the city, often 10 or 15 meters beneath the feet of people walking downtown, and it is visited in pieces, almost always by reservation and almost never by chance. Under the basilicas there are other basilicas, under the Umbertine buildings domus with mosaic floors, under the gardens of the Appian Way kilometers of funerary galleries dug into the tuff, under some 20th-century villa a reinforced concrete air-raid shelter. The problem is not a lack of sites: it is that each one has a different operator, a different booking system, hours that change and, in several cases, a closure under way that the visitor only discovers at the gate. The pages that follow line up what is under Rome, what you can visit, what is closed and how to book. Where a detail is not confirmed by an official source, it says that it needs to be checked.

Why there is another city under Rome

The walking level of ancient Rome lies on average between 4 and 15 meters below the current one, and this difference in level is the physical reason a visitable underground Rome exists. Apart from a minority of cases, these are not galleries dug on purpose, but ancient buildings that stayed in place and were buried by the slow rise of the ground: Tiber floods that deposited mud, rubble from fires and collapses leveled instead of removed, fill from building sites. For 20 centuries the ground level has risen, and what was on the ground floor has found itself in the cellar.

How the ground level rose

In the low city, between the Forum Boarium and the Campus Martius, the culprit is the river: before the 19th-century embankment walls every flood left a layer of silt that nobody removed. In the high areas, on the Palatine, on the Esquiline and on the Caelian, the mechanism is different: when a building collapsed, the cheapest way to build on top was to fill it with rubble and use it as a foundation. This is what happened under dozens of churches, and it is the reason excavations under a basilica almost always return a sequence and not a single building.

The layered basilicas: churches built on top of other churches

Basilicas with excavations open under the floor are the simplest and cheapest way to see underground Rome: almost all are downtown and are visited with an ordinary ticket without long waits. The principle is always the same: an early Christian or medieval church built over a Roman building, then raised, with the lower levels brought to light between the 19th and 20th centuries. The result is a descent in stages, where each flight of stairs corresponds to a few centuries.

San Clemente: three levels and a mithraeum at the bottom

The basilica of San Clemente, a few hundred meters from the Colosseum along Via di San Giovanni in Laterano, is the textbook case of Roman layering and the underground site to visit first if you visit only one. At street level is the medieval basilica, with the apse mosaic of the cross as a tree of life and the marble schola cantorum. One flight down you enter the early Christian basilica, in use from the fourth century, with the early medieval frescoes and the famous vernacular inscription of the legend of Sisinnius. Further down are the Roman buildings of the first century: a tenement block, warehouses and a mithraeum with the sculpted altar, where you hear the running water of an ancient conduit that is still active.

The complex is run by the Irish Dominican fathers. The archaeological area has a separate ticket from the upper church, which is free as a place of worship: the amount and hours should be checked on the basilica's website or by phoning the secretariat, because they have been updated several times and third-party pages often report old figures. For individuals booking is generally not required, for groups it is.

Santi Giovanni e Paolo and the Roman Houses of the Caelian

The Roman Houses of the Caelian, beneath the basilica of Santi Giovanni e Paolo, are the only complex of frescoed Roman dwellings visitable downtown with an independent entrance, open every day from 10 to 16, ticket office closing one hour before, at €10 full price and €8 reduced. You enter from the Clivo di Scauro, the little street flanked by buttress arches that links the Caelian to the Colosseum valley, and go down into a labyrinth of 20 rooms belonging to different buildings, between the second and fourth centuries: a multi-story rental house, a noble domus with a frescoed nymphaeum, shops.

The part that strikes the most is the so-called confessio, a room with painted martyrdom scenes, linked by tradition to Saints John and Paul, buried according to the Church's account in their own house: the link is debated among scholars and should be reported as tradition, not as established fact. The confessio is not accessible to wheelchairs, the rest of the route partly is. Guided visits are bought separately and the site closes on January 1 and December 25.

Santa Cecilia in Trastevere: the domus under the nave

Beneath the basilica of Santa Cecilia in Trastevere you visit an archaeological area with structures from the Republican and imperial ages: basins, walls in opus reticulatum, rooms long interpreted as a tannery and today read with more caution, and some sarcophagi. Tradition identifies these remains with the saint's house, where the martyrdom is said to have taken place: here too the link is devotional, and archaeologists treat it as such. The neo-Byzantine crypt of the early 20th century, with its polychrome columns, is the element that stays most in the mind.

The visit has a separate contribution, also required for Pietro Cavallini's Last Judgment in the nuns' choir, and depends on the hours of the Benedictine community: they are short and variable hours, to be checked by phone before going. Those in the area can pair it with the basilica of Santa Maria in Trastevere and the Museo di Roma in Trastevere, a few minutes away on foot.

San Crisogono: the early Christian basilica under the floor

The church of San Crisogono, in Piazza Sonnino in Trastevere, preserves under the nave the remains of an early Christian basilica of the fourth or fifth century, with apse, annexes and detached early medieval frescoes: you go down a small staircase in the transept into a low, damp space, much less frequented than San Clemente. Access involves a small contribution and depends on the church's hours, with the usual afternoon closure: it's best to call the parish first, because the descent is suspended when staff is lacking.

Santi Silvestro e Martino ai Monti: the Roman hall under the nave

Beneath the basilica of Santi Silvestro e Martino ai Monti, on the Oppian Hill a stone's throw from Santa Maria Maggiore, a large Roman room of the third century in opus listatum is preserved, about 20 meters long. Long identified with the titulus Equitii, the house of a Christian who supposedly hosted the assemblies before the peace of the Church, it is now interpreted rather as a reused civil structure. The visit depends on the Carmelite community that officiates in the church, is requested in the sacristy and has no public price list: it is one of the underground sites easiest to miss and simplest to see, if you happen to come at the right time.

The other churches with something underneath

The list of Roman churches with ancient structures under the floor is long and largely not open to ordinary visits, but some are worth a detour. The basilica of the Santi Quattro Coronati on the Caelian preserves under the nave the footprint of a much larger early medieval basilica. The basilica of Santa Pudenziana rests on a Roman bath complex partly visible from the nave, and right next to it the basilica of Santa Prassede keeps the chapel of San Zenone and a ring crypt. The basilica of San Saba has ancient rooms below the level of the church. San Nicola in Carcere is the most spectacular case among the lesser known: the church incorporates three Republican temples of the Forum Holitorium and you walk among their columns in the underground, with a visit by contribution run by the parish.

To these are added the papal complexes. Beneath St. Peter's Basilica are the Vatican Grottoes, with free access during the basilica's hours, and further down the Vatican necropolis, visitable only by reservation at the Excavations Office of the Fabbrica di San Pietro, in very small groups and with an absolute ban on photography. Beneath the basilica of St. John Lateran extends an archaeological area with remains of Roman houses and of the barracks of the equites singulares, open intermittently and with a separate ticket. In the Forum, Santa Maria Antiqua is buried under the slopes of the Palatine and keeps Rome's most important cycle of early medieval frescoes, included in the ticket of the Colosseum Archaeological Park.

The domus and buried cities under the palazzi

The second family is that of the Roman houses rediscovered during construction work in the very center and turned into museums under the modern building. They are the best kept sites, with the best lighting and the most comfortable routes, and the ones that work best with children, because the story is visual and the visit is short.

Domus Romane di Palazzo Valentini

The Domus Romane di Palazzo Valentini, beneath the seat of the Metropolitan City a few meters from the Trajan's Markets and the Forum of Trajan, are visited only on a guided route at fixed turns, with a full ticket at €15, an open ticket at €16, a reduced ticket at €9 and a presale fee of €1.50. They open every day except Tuesday: from March 1 to October 31 from 10 to 19, last turn at 17:30, from November 1 to the end of February from 10 to 18, last turn at 16:30. For groups booking is mandatory through the contact center, for individuals it is strongly recommended at least the day before, and it becomes mandatory for those with mobility difficulties who need assistance.

You see the remains of two aristocratic domus of the imperial age, with colored marble floors, traces of bath systems and the foundations of later structures. The difference from an ordinary dig is the system of projections and virtual reconstructions that clothes the walls: elevations, furnishings and colors appear on the walls. It is a museographic choice that divides opinion, because it tells more than the ruin shows, but for a non-specialist audience it is the most effective way to understand what a rich house of the fourth century was like. The route lasts about an hour and backpacks and bulky bags are not allowed.

Vicus Caprarius, the City of Water under the Trevi Fountain

The Vicus Caprarius, a few steps from the Trevi Fountain, is open Tuesday to Sunday from 11 to 17 and closed on Monday. You go down into the space of the former Trevi cinema, where the works of the 1990s intercepted a Roman block: a rental insula turned in the imperial age into a luxury domus and, above all, a castellum aquae, the collection basin of the Aqua Virgo, the aqueduct that still feeds the fountain on the surface today. The water still flows in the site and you can hear it.

The small exhibition gathers the materials from the dig: coins, amphorae, architectural elements and a marble head of Alexander Helios that has become the symbol image of the place. The ticket price is not published in a stable way and should be asked of the management, which also takes bookings for guided and private visits. It is a short visit, between 20 and 40 minutes, to fit in between the fountain and the Pantheon.

Domus Aurea: the building site you can visit

The Domus Aurea on the Oppian Hill is visited only on a guided route on weekends and with mandatory booking, because the monument is both an archaeological site and a permanent restoration site. Of the entire palace that Nero had built after the fire of 64, designed by Severus and Celer and decorated by the painter Fabullus, you walk through only the Oppian pavilion, which the successors filled with earth to build the Baths of Trajan on top: that very fill saved the frescoed vaults.

Inside it is cold and very damp, normal for an underground space covered by a public park, and this explains why the restoration never ends. The visit includes a virtual reality part that restores the volume of the rooms. Ticket price and the calendar of turns change from season to season and should be checked on the website of the Colosseum Archaeological Park: in high season places sell out weeks in advance. The rooms, rediscovered in the Renaissance as grottoes, are the origin of the word grotesques, the decorative repertoire that passed from there to Raphael and to half of Europe.

Crypta Balbi: closed for renovation

The Crypta Balbi, seat of the National Roman Museum in Via delle Botteghe Oscure, is closed for renovation works since January 9, 2023 and is therefore not visitable: anyone who still finds it listed as open in guides and itineraries is reading outdated information. It is a closure that weighs, because there the passage from the ancient city to the medieval one could be read better than elsewhere: beneath the museum is preserved the porticoed courtyard attached to the Theater of Balbus, and above it the sequence of houses, shops and convents that occupied its space. The reopening should be checked on the National Roman Museum's website, the other venues of the circuit remain open, from Palazzo Massimo alle Terme to the Octagonal Hall and the Baths of Diocletian.

The mithraea: the underground temples of the god Mithras

More than 40 mithraea are known in Rome, of which only a minority is visitable and almost always by reservation with limited numbers. The cult of Mithras, spread in the empire between the second and fourth centuries above all among soldiers, officials and merchants, was practiced in dark, narrow spaces, made in existing basements or built on purpose to resemble a cave: a rectangular hall with two side benches, the podia, and at the back the tauroctony, that is Mithras killing the cosmic bull.

Mithraeum of the Circus Maximus

The mithraeum of the Circus Maximus, discovered in 1931 during work for a depot in the former Pantanella pasta factory, is visited with mandatory booking at the number 060608, active from 9 to 19, with entry allowed only to accompanied groups and a maximum of 25 people per visit. The ticket costs €4 full price and €3 reduced, with free entry for Rome residents and for MIC card holders, the guided visit is not included in the ticket. The site is not accessible to wheelchairs.

It is the largest mithraeum among those visitable in the city, made in the third century inside an imperial public building, with preserved podia and a marble relief of the tauroctony. You go down through an inconspicuous opening on the side of Piazza della Bocca della Verità, a short distance from the Arch of Janus and from Santa Maria in Cosmedin, and this makes it easy to pair with a walk in the Foro Boario and the Mouth of Truth.

Mithraeum of Santa Prisca

The mithraeum of Santa Prisca, on the Aventine, has visits temporarily suspended: before planning the climb it's best to check the resumption of openings on the official channel of the Capitoline Superintendency, which runs it together with the contact center 060608. It is a pity, because together with the Barberini mithraeum it is one of only two painted mithraea in Rome: the walls preserve a procession of initiates with the masks of the grades, painted in two overlapping phases, and a sculptural group with the tauroctony. It was discovered in 1934 under the church and excavated by the Dutch Institute in the 1950s.

Barberini mithraeum: you can't visit it from the Galleria Nazionale

The Barberini mithraeum generates a lot of confusion. The shrine is under the Savorgnan di Brazzà villino, built in 1936 on Via San Nicola da Tolentino, a building owned by the Armed Forces Officers' Club: it was the digging of that building's foundations that intercepted it. It cannot be reached from the visitor route of Palazzo Barberini, that is from the rooms of the Galleria Nazionale d'Arte Antica, although the name and the topographical closeness lead you to think so. Access depends on the owner and the competent superintendency, happens only with special openings or authorized visits for small groups, and there is no ordinary ticket office: the entry for the Barberini mithraeum remains on the site. When it is open, you see one of the best preserved Mithraic frescoes in the world, with the tauroctony in the center and the side panels with the episodes of the myth.

The mithraeum of San Clemente and the others

The mithraeum of the third level of San Clemente is in practice the only Roman mithraeum visible without a reservation, with the normal ticket of the archaeological area: a hall with a barrel vault decorated as fake rocks, the two side podia and the altar with the tauroctony in the center. Next to it is preserved the so-called Mithraic school, a room with benches probably used for the instruction of initiates. The largest mithraeum known in Rome is instead under the Baths of Caracalla: it opens only with special routes, not included in the normal tour of the baths, so availability should be checked with the Archaeological Park. Anyone who wants to see a mithraeum without uncertainty can head for Ostia Antica, where more than a dozen are preserved in the open air, included in the ordinary ticket of the dig.

The Christian catacombs: five open, dozens closed

The catacombs of Rome number more than 60, extend for hundreds of kilometers of galleries and almost all belong to the Holy See, administered by the Pontifical Commission for Sacred Archaeology: five are open to the public with regular guided visits, the others are visited only with a motivated authorization or not at all. It is the most important distinction, because many guides list catacombs that have been closed for decades.

How the visit works

You never go into the catacombs alone: you go in as a group with an escort, along a fixed route, in visits lasting between 30 and 45 minutes. The galleries are narrow, damp, with a constant temperature of around 15 degrees Celsius and a floor that is uneven in places, photographs are normally forbidden and most routes are not accessible to wheelchairs. The catacombs are not the undergrounds of churches: they are suburban cemeteries dug outside the walls, because Roman law banned burials inside the pomerium, and that is why they are found along the great consular roads and not downtown.

San Callisto

The catacombs of San Callisto, on Via Appia Antica at number 110, are open from 9 to 12 and from 14 to 17, closed on Wednesday, on January 1, at Easter and on December 25, plus an annual period between January and February. The last visit of the morning starts at 12 and that of the afternoon at 17: visits start every 30 minutes, last about 40 minutes and are done in groups of at least two people with a staff member. Online booking is required. The ticket price is not clearly published and should be confirmed when booking or by calling 06 5130151.

It is the most extensive and most visited complex: 20 kilometers of galleries on several levels, the Crypt of the Popes with nine bishops of Rome of the third century, the crypt of Santa Cecilia with the frescoes and the copy of Stefano Maderno's statue. It is reached along the Appia Antica Park, a short distance from the church of Domine Quo Vadis.

San Sebastiano

The catacombs of San Sebastiano, a little farther along the Appia, are the only complex never abandoned: the very name catacomb, from the Greek for cavity near the depression, was born here and then extended to the other underground cemeteries. The most surprising part is not the galleries but the so-called piazzola, a widening with three pagan mausoleums of the second century perfectly preserved, left standing because they were buried by the embankment on which the apostolic memorial was later built, and the triclia with the graffiti of pilgrims invoking Peter and Paul. Hours, closing days and price should be checked with the complex, next to the basilica of the same name and the Mausoleum of Cecilia Metella.

Domitilla

The catacombs of Domitilla, on Via delle Sette Chiese, are the most extensive in Rome by linear development and the only ones with a semi-underground basilica inside, dedicated to the martyrs Nereus and Achilleus, still used for services. The complex is rich in early Christian frescoes, from the Good Shepherd to biblical scenes, and incorporates an older pagan hypogeum. The route has wide stretches, which makes it one of the best choices for those who suffer from claustrophobia. Hours and cost should be checked on the site's website.

Priscilla and Sant'Agnese, on the north side

The catacombs of Priscilla, on Via Salaria, are known for the cubicle of the Velata, for one of the oldest known Marian depictions and for the Greek chapel with its stucco decorations: they are looked after by the Benedictine sisters and the visit is booked through the site. Not far away, beneath the basilica of Sant'Agnese fuori le mura, you visit the catacombs of Sant'Agnese, with well-preserved galleries and a regular layout, a few steps away is the Mausoleum of Santa Costanza, with the mosaics of the annular vault. It is the most effective underground pairing outside the Appia.

The minor catacombs and the closed ones

There is then a second list, that of the catacombs that open only on motivated request to the Pontifical Commission for Sacred Archaeology, for study or for accompanied groups. Among these the catacombs of Commodilla, famous for the oldest vernacular inscription in Rome, and the catacombs of Santa Tecla, where the restorations brought back the oldest portraits of the apostles, on Via Portuense, the Generosa catacombs complex and the necropolis of Via Portuense. The rule is always the same: you write, you wait, you go when the authorization arrives. Showing up at the gate is of no use.

The Jewish catacombs: the oldest and the least accessible

Six Jewish catacombs are known in Rome, of which two survive in readable condition, and neither of the two is open to free visits with a ticket office. They are documents of enormous importance, because Rome's Jewish community is the oldest of the Western diaspora and because in some cases these galleries predate the Christian catacombs, which overturned an old belief about the origin of the underground burial ground in Rome.

Vigna Randanini

The Jewish catacomb of Vigna Randanini, between Via Appia Antica and Via Appia Pignatelli, extends for about 700 meters of galleries with cubicles, arcosolia and paintings, among them Jewish symbols such as the menorah, the lulav and the shofar, alongside classical decorative subjects. It is on private property and has no regular opening: visits happen only in exceptional cases, with authorization and in accompanied groups. Anyone who wants to understand the context can visit the Jewish Museum of Rome beneath the Synagogue of Rome, which displays materials and reconstructs 2,000 years of the community's history.

Villa Torlonia

Beneath the park of Villa Torlonia, on the Nomentana, there are two Jewish catacombs discovered in 1919, with frescoed galleries and inscriptions in Greek, Latin and Hebrew. They are not open to the public: access is reserved for authorized research and very rare openings. The park on the surface can be visited freely, and its museum buildings, from the Casino Nobile to the Casina delle Civette, are open with an ordinary ticket. In the same park is the bunker discussed further on.

Hypogea, columbaria and painted tombs

Between the collective catacombs and the great domus there is an intermediate category: the family or association tombs dug underground, often decorated with surprising quality and almost always with access limited to a very few people. They are the most fragile places of underground Rome and for that reason the hardest to see.

Hypogeum of the Aurelii

The hypogeum of the Aurelii, on Viale Manzoni, is run by the Pontifical Commission for Sacred Archaeology and is not open to the public on a regular basis: visits are obtained only on authorized request, by writing to the body. It was discovered by chance in 1919 near Porta Maggiore and preserves cycles of frescoes from the first decades of the third century, of debated interpretation: pastoral scenes, banquets, a figure of a philosopher, an entry into the city on horseback, a figure read by some as Christ and by others as a teacher of wisdom. It must be said clearly: the religious interpretations of its paintings are academic hypotheses in conflict with each other, not established facts.

Hypogeum of Via Dino Compagni

The hypogeum of Via Dino Compagni, also known as the catacomb of Via Latina, is perhaps the most extraordinary painted complex in the Roman underground and is visited only by authorized reservation from the Pontifical Commission for Sacred Archaeology, in very small groups. Discovered in 1955, it preserves frescoed cubicles of the mid-fourth century in which Old Testament scenes coexist with the labors of Hercules and, in one room, with what has been read as an anatomy lesson scene, with colors of rare vividness. There is no ticket office or schedule: the request must be sent to the body well in advance.

Underground basilica of Porta Maggiore

The underground basilica of Porta Maggiore, in Piazzale Labicano, is accessible only with special openings and on the occasion of events, with booking through the online service of the Special Superintendency of Rome. It was discovered in 1917 during work on the railway line and lies at a depth of about 12 meters: it is a hall with three naves and an apse, dug into the ground and then lined, entirely decorated with white stuccoes representing mythological scenes and allegorical figures, dated to the first half of the first century CE. Its function is debated: the most widespread reading considers it the meeting place of a Neopythagorean community, but it is a hypothesis, and others read it as a funerary hall or private basilica.

Columbarium of Pomponius Hylas

The columbarium of Pomponius Hylas, near the Aurelian Walls on Via Latina side, is closed since August 1, 2024 for redevelopment works financed by the PNRR. When it is open it is visited only in groups of at most seven people with mandatory booking at 060608, with a ticket at €4 full price and €3 reduced and free entry for Rome residents and MIC card holders. Discovered in 1831 by the marquis Pietro Campana, it is a burial chamber in use between Tiberius and Claudius, with a vault with plant motifs, niches for the urns adorned with small columns, frescoes and stuccoes, and a glass-paste mosaic tablet with the owners' names above the stairs. The recurring theme is Orpheus. In the same area is the Museum of the Walls, which allows you to walk along a stretch of the ancient walkway.

Aqueducts, water castles and the Cloaca Maxima

The truly enormous part of the Roman underground is neither funerary nor residential: it is hydraulic. Aqueducts and sewers produced hundreds of kilometers of conduits, many still intact and in some cases in operation, and it is the least visitable portion of all, because these are active or unstable infrastructures.

The aqueducts: what you see above and what below

Of the Roman aqueducts the spectacular part is above ground, in the arches of the Aqueducts Park, among the remains of the Anio Novus, the Claudia, the Marcia and the Renaissance Acqua Felice. But the stretch on arches was a minority: almost the whole route was underground, in channels dug into the tuff with regular inspection shafts, and those channels still exist under the countryside and under the neighborhoods. They are not visited: only researchers and authorized caving groups enter them. The only ancient aqueduct still in operation is the Aqua Virgo, which feeds the Trevi Fountain and the fountains of Piazza Navona, and the place where you can observe it without special permits is the Vicus Caprarius.

The Cloaca Maxima

The Cloaca Maxima is not visitable and there is no authorized tourist route inside it, because some stretches are still part of the active sewer system. It is the great collector that from the archaic age drained the Forum valley toward the Tiber. What you see is the outlet, the large arch on the Lungotevere between the Tiber Island and Ponte Palatino, plus some stretches in view in the Forum area. Anyone who finds offers of visits to the Cloaca Maxima should be careful: almost always they are other tunnels, sold under a more attractive name.

Ancient monuments that became underground

Some buildings were not born underground but ended up there, because the modern city covered them: you visit them by going down under a square or into a service hypogeum.

Stadium of Domitian under Piazza Navona: currently closed

The archaeological area of the Stadium of Domitian, beneath Piazza Navona, is currently closed to the public according to the notice published on the official website of the archaeological site, which refers to the Capitoline Superintendency for Cultural Heritage for information. Anyone who still finds tickets and packages that include it must check before buying. When it is accessible, you go down from Via di Tor Sanguigna into the substructures of the northern hemicycle of the stadium built by Domitian in 86 CE for athletic contests in the Greek style: these are the rooms that supported the stands and that dictated to the upper level the elongated, curved shape of the Baroque square, which is therefore the cast of an ancient sports building.

The hypogea of the Colosseum

Beneath the arena of the Colosseum extend the hypogea, the system of corridors, cages, winches and lifts that brought men and animals onto the stage: they are not included in the ordinary ticket, they are visited with a specific access ticket and a guided route of limited availability, to be booked well in advance on the official channel of the Colosseum Archaeological Park. It is the most requested underground visit in Rome and the one that sells out first.

The 20th-century underground: shelters, bunkers and the metro

Underground Rome does not end with antiquity: the 20th century dug as much as the Romans and more, for military reasons first and for public transport later, and part of this recent underground is visitable.

Air-raid shelters and bunkers

Rome was bombed starting on July 19, 1943, with the attack on the San Lorenzo district, and in the preceding years it had equipped itself with shelters of every kind: reinforced cellars, galleries, adapted pozzolana quarries and a few real bunkers. Beneath Villa Torlonia, Mussolini's residence from 1925 to 1943, there are three successive shelters, the last a reinforced concrete bunker with a double entrance and an air filtering system, built in 1942 and never completed: it is visited by reservation with a guided route, as part of the Musei in Comune, on limited days and hours. Other shelters open on special occasions, like the one in Villa Ada, carved into the hill for the royal family, and the shelters of the EUR under the Palazzo degli Uffici. None has free entry.

Metro line C and archaeology

Metro line C is the largest urban archaeological dig in Europe and has changed what we know of Rome's underground. Every station shaft crossed the complete stratigraphy of the city, bringing back military barracks of the Hadrianic age, a luxury building near the Amba Aradam, medieval houses, Republican structures and even fruits and seeds preserved in the damp levels. Part of the finds is turned into museum displays inside the stations, with showcases and reconstructions: a diffuse museum visited with the metro ticket, the cheapest form of underground Rome.

Three tested underground itineraries

Underground Rome is not visited at random: the sites have short hours, fixed turns and real distances between them, so it's best to group them by area. Here are three combinations that hold up as far as hours go, provided you book in advance whatever needs booking.

Half a day on the Caelian

In the morning the basilica of San Clemente for the three levels and the mithraeum, then 10 minutes on foot to the basilica of the Santi Quattro Coronati and finally, along the Clivo di Scauro, the Roman Houses of the Caelian, which close at 16 with the ticket office at 15. Anyone with time left continues toward Santo Stefano Rotondo or goes down to the Colosseum.

A day on the Appia

With the catacombs of San Callisto in the morning and the catacombs of San Sebastiano in the afternoon, the day builds itself: in between are the church of Domine Quo Vadis, the Mausoleum of the Fosse Ardeatine, the Mausoleum of Cecilia Metella and the paving stones of the Appia Antica Park. Careful: almost all the catacombs close between 12 and 14, and San Callisto closes on Wednesday. Anyone with time can push on to the Villa of the Quintilii.

Half a day in the Baroque center

From the Trevi Fountain you go down to the Vicus Caprarius between 11 and 17, then walk to the Trajan's Markets and the Domus Romane di Palazzo Valentini, with the turn booked. Both close one day a week, the Vicus Caprarius on Monday and Palazzo Valentini on Tuesday: the combination works from Wednesday to Sunday. At the end you can add the Mamertine Prison at the foot of the Capitoline Hill or, on the surface, the Capitoline Museums.

How to prepare a visit underground

A good day of underground Rome depends almost entirely on preparation, because these sites have low capacities, short hours and sudden closures.

Booking: who, how, when

The channels are few and worth learning. For the city-run monuments (mithraeum of the Circus Maximus, columbaria, hypogea, Villa Torlonia bunker) you book at the contact center 060608, from 9 to 19, or on the website of the Musei in Comune. For the Colosseum, Palatine, Domus Aurea and Baths of Caracalla you go through the Colosseum Archaeological Park. For the Christian catacombs you book on the website of the individual catacomb, run by a different congregation for each complex. For state sites like the underground basilica of Porta Maggiore you use the online booking of the Special Superintendency of Rome, for the domus run under concession, like Palazzo Valentini and the Vicus Caprarius, the operator's website. In high season two or three weeks in advance is not excessive.

Photographs, children, accessibility

The rules change from site to site and it's good to find out when you book. In the catacombs photography is normally forbidden, in the Vatican necropolis the ban is absolute, in the domus turned into museums you generally photograph without flash and without a tripod. Children handle short, visual visits well, like Palazzo Valentini and the Vicus Caprarius. Accessibility is the weak point of the system: many hypogeal sites are reached only by steep, narrow stairs, the mithraeum of the Circus Maximus is not accessible to wheelchairs, and neither is the confessio room of the Roman Houses of the Caelian.

Frequently asked questions about underground Rome

What can you really visit under Rome?

Under Rome you visit with a regular ticket the layered basilicas like San Clemente and the Roman Houses of the Caelian, the domus of Palazzo Valentini and of the Vicus Caprarius, the Domus Aurea on weekends by reservation, five Christian catacombs with a guided visit and some mithraea and columbaria of the Capitoline Superintendency, booking at 060608. Other sites, like the underground basilica of Porta Maggiore, open only with authorizations or special events.

Is the Stadium of Domitian under Piazza Navona open?

The archaeological area of the Stadium of Domitian under Piazza Navona is currently closed to the public, according to the notice published on the official website of the archaeological site, which refers to the Capitoline Superintendency for Cultural Heritage for information. Anyone who still finds tickets or packages that include it for sale must check before buying. The elongated, curved shape of the square remains, in any case, the cast of the ancient building, readable also from the surface.

How much is the ticket for the Domus Romane di Palazzo Valentini?

The Domus Romane di Palazzo Valentini cost €15 for the full ticket, €16 for the open formula that lets you choose date and time after purchase, €9 for the reduced ticket for young people from 6 to 17 years, €6 per student for school groups, plus €1.50 presale. Entry is free under 6 years and for visitors with disabilities. You enter only on a guided route at fixed turns and the site closes on Tuesday.

Can you visit the catacombs of Rome without a guide?

No: in the catacombs of Rome you always go in accompanied by a staff member, in a group and along a fixed route, with visits that last on average between 30 and 45 minutes. At San Callisto, for example, visits start every 30 minutes, last about 40 minutes and are done in groups of at least two people. Photographs are normally forbidden and most routes are not accessible to wheelchairs.

Can you visit the Barberini Mithraeum by going to Palazzo Barberini?

No: the Barberini mithraeum cannot be reached from the visitor route of the Galleria Nazionale d'Arte Antica at Palazzo Barberini. It is under the Savorgnan di Brazzà villino, built in 1936 on Via San Nicola da Tolentino and owned by the Armed Forces Officers' Club, and was discovered precisely during the digging of that building's foundations. Access happens only with authorized special openings and for very small groups, with no ordinary ticket office.

How much does the mithraeum of the Circus Maximus cost and how do you book?

The mithraeum of the Circus Maximus costs €4 for the full ticket and €3 for the reduced, with free entry for Rome residents who show a document and for MIC card holders. Booking is mandatory at the number 060608, active from 9 to 19, and entry is allowed only to accompanied groups with a maximum of 25 people per visit. The guided visit is not included in the ticket price and the site is not accessible to wheelchairs.

Can the Crypta Balbi be visited?

No: the museum of the Crypta Balbi, seat of the National Roman Museum in Via delle Botteghe Oscure, is closed for renovation works since January 9, 2023, and the reopening should be checked on the National Roman Museum's website. The other venues of the circuit remain open, from Palazzo Massimo alle Terme to the Baths of Diocletian and the Octagonal Hall, with part of the materials on the passage from the ancient city to the medieval one.

Can you enter the Cloaca Maxima?

No: the Cloaca Maxima is not visitable and there is no authorized tourist route inside it, because some stretches are still part of the active sewer system. You see the monumental outlet on the Tiber, the large arch between the Tiber Island and Ponte Palatino, and some stretches in view in the Forum area. The visits advertised as the Cloaca Maxima generally concern other tunnels.

Anyone who organizes visits in the Roman underground for work, as a guide or tour leader, knows that these sites require different handling from an open-air monument: limited turns, capacities of seven or 25 people, groups to keep together in dark, narrow spaces, and a plan B always ready for when a site closes without notice. On tourleaderpro.com you will find tools and materials designed for people who guide groups in Italy, from building the itinerary to the operational management of multiple bookings, and it is a useful reference for turning a list of underground sites into a day that really works.

Anyone instead building a trip to Italy who wants to understand how to fit underground Rome into a broader route, maybe with stops in other art cities or with spare days for the bookings that don't come through, can start from italyplanner.com, which thinks about the trip as a whole: how many days you really need in Rome, when it's best to come to find the sites open, how to alternate tiring visits and light days. The Roman underground rewards those who arrive prepared, and preparation begins long before going down the stairs.