Rome is built on Rome. Below every current street level are Republican, Imperial, and early Christian structures that the medieval city built on top of rather than clearing. Some are open to visitors.
Plan my Italy trip →Rome is built on Rome. Below every current street level are Republican, Imperial, and early Christian structures that the medieval city built on top of rather than clearing. The geological accumulation in the historic center is approximately 6-15 metres of human occupation compressed into the soil — each layer containing the evidence of a different civilization. Some of these underground layers are now open to visitors. Together they constitute one of the most extraordinary archaeological experiences available anywhere.
The Basilica di San Clemente (Via Labicana 95, near the Colosseum, €12) is a three-level vertical excavation of Roman urban history: the current 12th-century basilica at street level (extraordinary medieval apse mosaics); descend one level to the 4th-century AD early Christian basilica (complete with original frescoes depicting the life of St. Clement); descend again to the 1st-century AD Roman building underneath (a Republican-era house and a Mithraeum — a temple of the cult of Mithras, with the original altar stone and a water channel running below the floor from an underground spring). Each level is complete and accessible; the physical movement between them — through narrow stairs, from decorated medieval church to bare Roman stone to running water in a 2,000-year-old temple — is one of the most experientially concentrated archaeological visits in Italy. The underground spring (still running) explains the site's continuous occupation: fresh water was the determining factor in Roman settlement choice.
The Domus Aurea (Golden House) was the private palace complex built by Emperor Nero after the Great Fire of Rome in 64 AD — a construction project occupying approximately 50-100 hectares of central Rome (estimates vary) that included gardens, artificial lakes, and pavilions across the Palatine, Oppian, and Caelian hills. After Nero's death in 68 AD, the Flavian emperors buried the Domus Aurea complex under fill and built the Colosseum on the site of its artificial lake. The Oppian Hill pavilion (Via della Domus Aurea, open for guided tours at certain periods — check coopculture.it for current scheduling, approximately €16) has partially excavated rooms including the Octagonal Room (the only surviving Roman room with a concrete dome pre-dating the Pantheon) and the ceiling paintings that were rediscovered in the 15th century by Renaissance artists who lowered themselves into the buried rooms on ropes — Raphael, Michelangelo, Ghirlandaio, and Pinturicchio all visited and copied the grotesque decoration, directly influencing Renaissance ornamental style. The Domus Aurea has intermittent access due to ongoing structural conservation — check availability before planning.
Mithraism was a mystery religion popular among Roman soldiers and merchants from approximately the 1st-4th centuries AD — Rome has over 40 identified Mithraic temple sites (Mithraea), more than any other city in the Empire. The cult centered on the figure of Mithras slaying a bull (the tauroctony), a ritual meal consumed by initiates, and a series of initiation grades ascending from Corax (raven) to Pater (father). The religion was exclusively male, probably transmitted through military units, and spread across the Empire along military supply routes. Its theology — the soul's ascent through planetary spheres, cosmic combat between light and darkness, a sacred meal with bread and wine — shares structural features with Christianity that have been endlessly debated by scholars without consensus on the direction of influence. Mithraism had disappeared almost completely by the early 5th century AD, its temples systematically demolished or built over by the newly state-supported Christian church. The Rome Mithraeum most accessible to visitors: the one under the Basilica di San Clemente (accessible with entry ticket) and the Mithraeum beneath Santa Prisca on the Aventine (open by appointment through the Augustinian Fathers).
Crypta Balbi (Via delle Botteghe Oscure 31, part of the Museo Nazionale Romano, €10): excavations under a medieval monastery revealing layers from the Theatre of Balbus (13 BC) through the medieval period — the best demonstration of Rome's stratigraphic accumulation. Largo Argentina Sacred Area (now open at ground level since 2023 renovation — the sacred precinct with four Republican temples including the one where Julius Caesar was assassinated on March 15, 44 BC, identified by the ancient name "Curia of Pompey"). Circus Maximus Experience (underground visitor experience at Via del Circo Massimo — the ancient racetrack's structure partially excavated). Rome's Catacombs (San Callisto, San Sebastiano, Priscilla, Domitilla — the early Christian underground burial galleries, 60+ km total, four open to visitors at approximately €10 each).
Rome has approximately 60 catacombs — underground burial galleries cut into the soft tufa rock outside the city walls, used primarily by the early Christian community from the 2nd to 5th centuries AD. Four are regularly open to visitors: San Callisto (Via Appia Antica 110, €10 — the largest and most visited, containing the Crypt of the Popes where eight early popes are buried and the tomb of St. Cecilia before her relics were moved to Trastevere; 19 km of galleries on four levels, the most comprehensive catacomb visit); San Sebastiano (Via Appia Antica 136, €10 — contains the first identified tomb of a martyr in Rome and a Mithraeum); Priscilla (Via Salaria 430, €10 — contains the oldest known image of the Madonna and Child, 2nd-3rd century, and the "Fractio Panis" fresco — the oldest surviving depiction of the Eucharist); Domitilla (Via delle Sette Chiese 282, €10 — the most extensive, 17 km, with the best-preserved basilica built over a martyr's tomb). Best for a first visit: San Callisto for historical depth; Priscilla for the earliest Christian iconography.
Largo di Torre Argentina (Piazza di Torre Argentina, open daily since 2023 renovation, free entry) is a sunken archaeological area in the heart of the historical center containing four Republican-era temples — the largest concentration of Republican temples accessible in Rome, dating from the 4th to 2nd centuries BC. The temples are designated A, B, C, and D by modern archaeologists (their ancient dedications are debated, though Temple B is now identified as the Temple of Fortuna Huiusce Diei). The specific historical significance: the adjacent Curia di Pompeo (now under the buildings east of the square, partially visible) was the temporary meeting place of the Roman Senate when the permanent Senate building in the Forum was under renovation on the Ides of March, 44 BC. The archaeologist excavations of the 1920s identified a triangular pavement section adjacent to Temple B as the pedestal base of Pompey's statue — at whose feet Julius Caesar fell after being stabbed 23 times. The cat sanctuary that occupies the sunken area has been rehomed to the perimeter during the 2023 renovation, but the cats remain in the area.
The Crypta Balbi (Via delle Botteghe Oscure 31, part of the Museo Nazionale Romano circuit, €10) presents the most continuous archaeological stratigraphy visible in Rome: excavations under a medieval convent reveal, in ascending layers, the cryptoporticus (underground passage) of the Theatre of Lucius Cornelius Balbus (13 BC, the smallest of Rome's three theatres), the post-theatrical use of the cryptoporticus as a glass workshop (5th-6th century AD), the construction of medieval buildings on top of the theatrical ruins (8th-9th century), and the convent built above those in the medieval period. The museum's ground floor displays the archaeological sequence with extraordinary clarity — actual walls and floors from each period visible through glass panels in the floor and walls of the exhibition space. The combination of the medieval convent's preserved cloister (above ground) and the Roman theatrical ruins (below) is the most legible demonstration of Rome's sedimentary layers available to visitors.
Palazzo Valentini (Via IV Novembre 119, near Piazza Venezia — €12, tours run every 30 minutes, advance booking recommended at palazzovalentini.it) presents two complete Roman domus (private houses) excavated under a 16th-century palace, using digital reconstruction projected onto the archaeological surfaces to show the original rooms, their decoration, and their function. The technology: fiber optic lighting and projection mapped onto the actual walls and floors shows the rooms as they appeared when inhabited — frescoes, floor mosaics, furniture, and domestic objects reconstructed from archaeological evidence. The experience is significantly different from a conventional archaeological walk: you walk through the actual rooms while the walls are illuminated to show their original decoration. The adjacent section of the Column of Trajan's base and a fragment of the Forum of Trajan are also visible. Best for: visitors who find conventional uncontextualized ruins difficult to interpret — the digital reconstruction makes the Roman daily life immediately readable without requiring prior archaeological knowledge.
Three significant underground and hidden experiences within 10 minutes walk of the Colosseum: (1) Santi Quattro Coronati (Via dei Santi Quattro Coronati 20, free — a fortified medieval basilica with a secret garden cloister of extraordinary quality, the most peaceful space in this area of Rome; ring the convent bell for cloister access). (2) Santi Giovanni e Paolo (Piazza dei Santi Giovanni e Paolo — the basilica built over the houses of the two saints, with Roman domus excavations under the church visible via guided visit at €12, cenacolo.it). (3) Via Sacra archaeological deposits — the stretch of Via Sacra between the Arch of Titus and the Colosseum contains Republican-era road surface in some sections, visible where the modern archaeological path has been cut to show the original level. No ticket required for this external observation.
The five planning mistakes that ruin Italy trips: (1) No advance bookings for the essential sites: the Uffizi, Vatican Museums, Borghese Gallery, Colosseum, and Last Supper all require advance booking. Walking up without a booking adds 1-3 hours of queuing to each site. The combined booking time is 2 hours at a computer; the combined queuing time without bookings is 8-12 hours. (2) Driving into a ZTL zone in a hire car: Italy's Limited Traffic Zones in historic centers (Rome, Florence, Siena, Bologna, Venice-mainland) issue automatic fines of €100-300 per violation, detected by cameras. The hire car company adds an administration fee. The fine arrives by post weeks later. Prevention: know the ZTL hours for your destination before arriving. (3) Over-packing the itinerary: moving between a different city every night produces transport logistics rather than Italian experiences. The minimum time to have a genuine experience of a place: 2 nights. (4) Eating within 200 metres of a major monument: the restaurant density around the Colosseum, Vatican, Trevi Fountain, and the Uffizi is tourist-facing by design and by market. Walk 300 metres in any direction. (5) Exchanging currency at the airport: airport exchange rates add 8-15% to the transaction. ATM withdrawal directly from an Italian bank (Poste Italiane, UniCredit) at the local interbank rate is always better; notify your bank before traveling.
Dolce far niente — the sweetness of doing nothing — is not laziness. It is the Italian cultural position that unscheduled time, a coffee consumed without checking a phone, a piazza watched from a chair without an agenda, has intrinsic value rather than being an unproductive state to be minimized. Travelers who attempt to optimize every hour of an Italian trip consistently report, on return, that the specific memories they carry are: sitting in a campo at dusk with a glass of wine, the smell of a market at 7am, a conversation with a restaurant owner. Not the queue-efficient museum circuit. The dolce far niente prescription for travelers: build one morning per destination into the itinerary with no plan — a direction and a starting point but no timetable. The Italian city that emerges from unscheduled wandering is consistently more interesting than the one that emerges from a checklist.
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