The journey continues…
TOURISM HAS BEEN MY PASSION AND MY PROFESSION SINCE 1990. I BEGAN IN LA PLATA, ARGENTINA, AT EUROMAR TURISMO, THE AGENCY OWNED BY MY BELOVED FATHER, ORAZIO FILIPPO GRECO, BEFORE CONTINUING IN ITALY WITH ANDINA VIAGGI. MERLINTRAVEL GROWS FROM THAT EXPERIENCE AND THE DESIRE TO KEEP EXPLORING AND SHARING THE WORLD. THE JOURNEY CONTINUES…
LET’S SEE WHERE IT TAKES US.
The journey continues…
TOURISM HAS BEEN MY PASSION AND MY PROFESSION SINCE 1990. I BEGAN IN LA PLATA, ARGENTINA, AT EUROMAR TURISMO, THE AGENCY OWNED BY MY BELOVED FATHER, ORAZIO FILIPPO GRECO, BEFORE CONTINUING IN ITALY WITH ANDINA VIAGGI. MERLINTRAVEL GROWS FROM THAT EXPERIENCE AND THE DESIRE TO KEEP EXPLORING AND SHARING THE WORLD. THE JOURNEY CONTINUES…
LET’S SEE WHERE IT TAKES US.
Rome Guide 04 · Dome, water and Augustan memory
A route from the Pantheon's concrete hemisphere to the lost baths, temples, sundial and dynastic monuments of the Campus Martius — where one ancient plain survives as fragments inside the modern centre.
Plan the routeWhy this district matters
Ancient Rome's northern plain was first associated with military assembly, elections, exercise and burial beyond the early civic centre. Under Augustus and his successors it became a dense landscape of temples, porticoes, baths, gardens, commemorative monuments and dynastic claims. The Pantheon, Agrippa's baths, the Horologium, Ara Pacis and Mausoleum were not picturesque objects scattered through streets. They formed visual and political relationships across open ground.
The modern city conceals most of those connections. The Pantheon remains nearly complete because it became a church; the Basilica of Neptune survives as a rear wall; Agrippa's baths appear as a curved brick fragment between houses; an Egyptian obelisk moved from its Augustan setting now stands before Parliament. Even the Ara Pacis is encountered in a modern reconstruction and museum beside, rather than at, its ancient location.
This guide therefore reads Campo Marzio through orientation, ground level and displacement. It distinguishes Agrippa's first Pantheon from Hadrian's present building, ancient structures from later façades, original sculpture from recomposed fragments and astronomical evidence from attractive but disputed simplifications. Current access conditions remain provisional and must be checked at the official sites.
In Campo Marzio, the missing distances between monuments are part of the monument.
The route
Begin early at the Pantheon with an official timed ticket, then circle the building before moving through the hidden Agrippan district. Continue north through Piazza di Pietra and Montecitorio, where columns and obelisk recover the imperial scale. End at Ara Pacis and the Mausoleum, treating museum access and the currently restricted tomb as separate conditions.
Read the portico, threshold, rotunda, coffers and moving light before crowds make the interior difficult to study.
Circle to the Basilica of Neptune, Arco della Ciambella and Piazza della Minerva to recover a precinct now embedded in streets.
Walk to Piazza di Pietra, Montecitorio and San Lorenzo in Lucina, separating the Hadrianeum from the displaced Campense obelisk and buried meridian.
Finish at the Ara Pacis Museum and the Mausoleum of Augustus, comparing ancient programmes with the twentieth- and twenty-first-century square.
Ten chapters
The order follows the surviving Pantheon quarter north toward the displaced solar and dynastic monuments. Use the index to revisit one fragment without losing the ancient plain.
A Hadrianic rotunda carrying Agrippa's name
The best-preserved monumental interior of ancient Rome joins a conventional columned front to an unprecedented concrete hemisphere whose light still measures the room.
Sixteen granite Corinthian columns carry the portico, behind which immense bronze doors open into the circular basilica of Santa Maria ad Martyres. The interior diameter and height are both about 43.3 metres. Five rings of coffers reduce toward an oculus roughly nine metres wide, while the patterned floor drains rain through small holes. Chapels, royal tombs, Raphael's grave and Christian furnishings occupy the Roman shell without erasing its geometry.
Marcus Vipsanius Agrippa founded the first Pantheon between 27 and 25 BC within his Campus Martius programme. Fires damaged that building in AD 80 and 110. Hadrian's reconstruction, generally dated AD 118–125, reversed the earlier orientation and created the present portico-and-rotunda composition while retaining Agrippa's dedicatory inscription. In 609 the Byzantine emperor Phocas gave the building to Pope Boniface IV, who consecrated it as Santa Maria ad Martyres. Its continuous religious use was central to survival, although bronze and architectural elements were removed or altered over centuries.
Read the exterior as an intentional problem, not a seamless classical façade. The rectangular portico, intermediate block and circular drum meet with changes of height and construction that reveal a complex design history. Inside, stand away from the centre and follow how the coffers, exedras and pavement alternate circles and squares. The dome is not a uniform concrete bowl: its thickness and aggregate change upward to reduce weight. The oculus is structure, light source and climatic opening at once. The inscription preserves Agrippa’s Augustan name on a largely Hadrianic building.
The surviving rear wall of Agrippa's monumental ensemble
Behind the Pantheon, a brick wall and marine frieze preserve the edge of a basilica that once joined temple, porticoes and baths into one public complex.
Via della Palombella exposes the massive curving and rectilinear masonry attached to the Pantheon's rear. The remains are easily mistaken for an anonymous service wall because later buildings press close and the original interior is lost. Architectural fragments with dolphins, shells, tridents and vegetation survive from the marine decorative programme. The visible structure can be studied from the street and from exceptional Pantheon routes when available.
Agrippa built the basilica around 25 BC as part of the same programme as his Pantheon, baths and nearby porticoes. It probably commemorated naval victories and contained a large semicircular exedra. Fire in AD 80 damaged the complex, which was rebuilt in the Hadrianic period together with the Pantheon. After the roof collapsed in the Middle Ages, systematic spoliation and new construction reduced the basilica to the walls now incorporated behind the rotunda. Renaissance drawings preserve more of its former plan and decoration than the street view alone.
Use this fragment to correct the isolation produced by Piazza della Rotonda. The Pantheon was not a solitary round temple but one component in a larger public quarter. Trace the wall's relationship to the rotunda, then imagine circulation continuing toward baths and porticoes without inventing a complete elevation. The marine imagery does not make the building a bath; it supports its association with Neptune and Agrippa's naval identity. The present boundary between monument and ordinary street is later urban fabric laid across an ancient institutional precinct.
Rome's first great public bathing complex survives as a curve
A tall semicircular brick wall between houses is the most legible remnant of baths once supplied by the Aqua Virgo and opened to the Roman people.
Via dell'Arco della Ciambella narrows around a high curved wall with windows and later masonry pressed against it. The fragment belongs to a large round or apsidal hall of the baths, but the rest of the complex lies beneath the surrounding blocks. There is no unified archaeological park: understanding depends on the street, the surviving curve and a map of the ancient precinct.
Agrippa developed the baths between about 25 and 19 BC and bequeathed them for public use. The Aqua Virgo, completed in 19 BC, supplied water to this new Campus Martius institution. Ancient descriptions associate the complex with art, pools and a landscape extending toward the Stagnum Agrippae. Repeated repairs kept the baths functioning into late antiquity, but dismantling began in the early Middle Ages and their materials entered later buildings. The surviving Ciambella wall reflects later imperial phases rather than a pristine Augustan room.
Do not mistake a fragmentary curve for the complete plan. Its value is scale: the radius and height reveal how monumental interiors disappeared into the fine grain of medieval and modern property. Look at where ancient brick is cut by windows, roofs and party walls. The name Ciambella preserves the perception of a circular ruin, not evidence for a doughnut-shaped bath building. Link the site mentally to the Pantheon and Aqua Virgo; water infrastructure, spectacle and public access made Agrippa's programme coherent.
A medieval market square stages an Egyptian monument before Rome's rotunda
The square's fountain and small Egyptian obelisk create the famous frontal view of the Pantheon, but both belong to much later remakings of the Campus Martius.
Piazza della Rotonda is a dense pedestrian room framed by cafés and palaces, with the Pantheon portico on its south side. At the centre, Giacomo Della Porta's late-sixteenth-century fountain supports the Macuteo obelisk on an eighteenth-century base with dolphins. The obelisk is about 6.3 metres high, rising to roughly 14.5 metres with base and cross.
The granite obelisk was erected in Heliopolis under Ramses II and later transported to Rome for the Iseum Campense, the sanctuary of Isis and Serapis located in this district. Rediscovered near Santa Maria sopra Minerva, it stood by San Macuto before Pope Clement XI moved it onto the Piazza della Rotonda fountain in 1711. The piazza itself evolved from an active market and low-lying urban space whose level rose around the ancient Pantheon.
Separate the picturesque composition from ancient topography. The obelisk did not mark the Pantheon in antiquity, and the fountain is a papal intervention. Their alignment nevertheless demonstrates how post-antique Rome used ancient material to organise public space and Christianised it with heraldry and a cross. From the fountain, compare the present square level with the lower base of the Pantheon portico. That difference measures accumulated streets and the selective excavation of the monument's threshold.
Gothic Rome stands over a district of Egyptian cults
Behind the Pantheon, a plain church façade, rare Gothic interior and Bernini's elephant carry the memory of an ancient sacred quarter transformed repeatedly.
Piazza della Minerva is dominated by the restrained façade of Santa Maria sopra Minerva and the small Egyptian obelisk raised on an elephant designed by Bernini and carved by Ercole Ferrata in 1667. Flood plaques on the church record destructive Tiber levels. Inside, pointed vaults, nineteenth-century colour, the Carafa Chapel, Michelangelo's Risen Christ and major tombs form a dense Dominican monument.
A church existed here by the early Middle Ages, while the present Gothic rebuilding began after the Dominicans settled in the thirteenth century. The name refers to ancient cult topography traditionally associated with Minerva, but the wider district also contained the Iseum Campense of Isis and Serapis. The sixth-century-BC obelisk came from that Egyptian sanctuary. Renaissance and nineteenth-century interventions substantially reshaped the church interior, so its current blue-and-gold appearance is not an untouched medieval surface.
Use the square to read three different claims on antiquity. The church name preserves a learned memory of Minerva; the obelisk is an actual Egyptian object relocated from a Roman cult complex; Bernini's elephant is a papal Baroque frame. None should be collapsed into a single continuous sanctuary. Inside, distinguish Gothic structure from later decoration and approach the flood plaques as urban evidence: the Campus Martius was a river plain before it became a protected monumental centre.
An imperial temple became the wall of a modern institution
Eleven colossal columns survive above the ancient pavement because the Temple of Hadrian was repeatedly absorbed into later buildings rather than isolated as a ruin.
Piazza di Pietra is a narrow urban room dominated by eleven Corinthian columns and part of the entablature on the north side of the temple. The ancient pavement lies several metres below the present square. In 1879 Virginio Vespignani incorporated the remains into the Stock Exchange building, now associated with the Rome Chamber of Commerce. A model and interior interpretation help restore the temple's lost scale when accessible.
Antoninus Pius dedicated the temple in AD 145 to his deified predecessor Hadrian. It stood in a large porticoed precinct and displayed reliefs personifying provinces of the empire. Spoliation removed most of the structure, while houses and institutional buildings reused the surviving colonnade. The nineteenth-century façade did not merely preserve an archaeological object: it made ancient columns part of a modern architecture of commerce.
Begin at the exposed ancient pavement to recover the height difference hidden by the piazza. Then follow how columns, entablature and modern wall belong to different structural systems. The conventional name Temple of Hadrian remains useful, although current institutional language often includes Vibia Sabina and Hadrian. Avoid treating the surviving side as the temple front. Its original approach faced toward Via del Corso, and the present square reveals a flank incorporated after the surrounding city changed orientation.
Augustus's solar marker now stands before Parliament
An Egyptian obelisk brought to Rome as the gnomon of an Augustan solar installation was recovered in fragments and re-erected in a new political square.
The red-granite obelisk rises in Piazza di Monte Citorio before the curved façade of Palazzo Montecitorio, seat of the Chamber of Deputies. The shaft is about 21.8 metres high and reaches nearly 34 metres with base and globe. Modern pavement lines recall its timekeeping function, but the present setting dates from the late eighteenth century and later restorations.
Psamtik II erected the obelisk at Heliopolis in the sixth century BC. Augustus brought it to Rome in 10 BC and placed it in the Campus Martius as the gnomon of a monumental solar installation. Subsidence, flood, earthquake or fire contributed to its collapse and burial. Benedict XIV ordered its extraction in 1748; it was found broken and fire-damaged. Giovanni Antinori re-erected the restored shaft in its present position in 1792. The square had already been shaped by the papal palace begun by Bernini and completed by Carlo Fontana.
The obelisk is authentic ancient material in a displaced urban relationship. Its Augustan base inscription and Egyptian hieroglyphs belong to different moments; its present globe and parliamentary backdrop add further ones. Do not use the modern pavement as a reconstruction of the entire ancient Horologium. It is an evocative reference at a new location. The most productive comparison is with the buried meridian remains toward San Lorenzo in Lucina and the Ara Pacis farther north.
A buried meridian corrects the myth of one enormous sundial
Fragments below the modern district preserve Greek calendar inscriptions and the line of a solar installation whose exact ancient form remains debated.
Evidence for the meridian or solar pavement survives below private buildings between Via di Campo Marzio and San Lorenzo in Lucina rather than as an open-air monument. A visible or visitable segment depends on current access arrangements. Greek inscriptions name zodiac signs and seasonal information, while the obelisk that cast the shadow now stands in Piazza Montecitorio.
Augustus installed the obelisk in 10 BC within a programme linking time, imperial victory and the northern Campus Martius. Modern scholarship has revised the older image of a vast dial covering the entire plain. Excavated pavement is generally associated with a later Domitianic restoration or version, after flood and subsidence altered the Augustan installation. The relationship between shadow, calendar and Ara Pacis remains important, but popular claims that the shadow struck the altar on Augustus's birthday require caution.
This is a chapter about evidence below access level. Treat the incised pavement as the primary object and diagrams as interpretation. Separate three questions: the original Augustan instrument, the later pavement now excavated and modern attempts to reconstruct solar alignments. The lost open sky is essential, because the gnomon's shadow once operated across a broad surface rather than inside a basement. Walking the distance to the present obelisk makes its displacement measurable.
An Augustan altar survives through excavation and recomposition
The marble enclosure joins procession, myth, sacrifice and vegetal abundance in a state monument reconstructed from fragments inside a modern museum.
The Ara Pacis stands inside Richard Meier's museum on Lungotevere in Augusta. Visitors can circulate around the rectangular marble enclosure, compare the two doorways, study the processional friezes and enter toward the altar. The bright controlled interior makes carving legible but is not the monument's ancient outdoor setting. Fragments were excavated, transferred and recomposed over centuries; missing fields remain modern restoration.
The Senate decreed the altar in 13 BC after Augustus returned from Spain and Gaul; it was consecrated on 30 January 9 BC. The monument stood beside the Via Flaminia in the northern Campus Martius. Rising ground and flooding buried it. Fragments emerged from the sixteenth century onward beneath Palazzo Fiano, and a major recovery campaign in 1937–38 enabled reconstruction inside Vittorio Ballio Morpurgo's pavilion. The current museum opened in 2006, retaining the twentieth-century relocation beside the Mausoleum rather than returning the altar to its exact ancient site.
Keep monument, fragments and reconstructed envelope distinct. On the lower zone, the scrolling acanthus is highly ordered rather than simply decorative; above it, civic procession and mythic panels connect family, priesthood, origin and sacrifice. Identification of every figure is not equally certain. Move around both long sides before entering, because the programme depends on correspondence and difference. Then use the museum's relationship with the Mausoleum to understand a modern Augustan ensemble that is historically meaningful but not the ancient alignment.
A dynastic tomb became fortress, garden, arena and concert hall
The largest known circular tomb of the ancient world survives as a stripped concentric structure whose later uses are inseparable from its present appearance.
The Mausoleum stands at the centre of a redesigned pedestrian Piazza Augusto Imperatore, opposite the Ara Pacis Museum and framed by twentieth-century buildings. Its outer drum, radial walls and central core remain far lower and barer than the ancient monument. Regular interior visits have been suspended since June 2022 while restoration and access work continue, so the public condition must be checked directly before planning entry.
Octavian began the tomb in 28 BC after the victory at Actium. With a diameter of about 87 metres, the structure contained concentric rings, radial compartments, a southern entrance and a central burial core, once covered by an earth mound and evergreen planting. It received members of the imperial family over generations. Later it became a fortified stronghold, Soderini garden, Correa arena and the Augusteo concert hall. Demolitions between 1936 and 1938 stripped post-antique layers and isolated the tomb within Morpurgo's monumental square. Recent works have again redefined access and the surrounding public space.
Resist reconstructing the monument as a simple green hill. The surviving masonry records a complex radial engineering system, while the loss of its travertine skin and upper mound makes the ancient exterior difficult to recover. Equally important are the absences created in the 1930s, when an inhabited quarter and the concert hall were demolished to expose an imperial ruin. The new square reconnects levels and pedestrian routes but becomes another historical frame. Compare the tomb with the Ara Pacis as a relationship remade twice: first by Augustus across the Campus Martius, then by modern urban policy.
The district through time
From Agrippa’s Augustan programme to the renewed Piazza Augusto Imperatore, these dates track survival, displacement and reconstruction across Campo Marzio.
Augustus begins his Mausoleum and Agrippa develops the first Pantheon within the Campus Martius.
The Aqua Virgo supplies Agrippa's public baths and water landscape.
The Ara Pacis is decreed and consecrated in the northern Campus Martius.
The Campense obelisk is installed as the gnomon of an Augustan solar instrument.
Fires damage the Agrippan Pantheon and surrounding monumental complex.
Hadrian rebuilds the Pantheon in substantially its present portico-and-rotunda form.
Antoninus Pius dedicates the temple to the deified Hadrian in the porticoed precinct now Piazza di Pietra.
The Pantheon is consecrated as Santa Maria ad Martyres, establishing continuous Christian use.
Ancient Egyptian obelisks are re-framed in Piazza della Minerva and Piazza della Rotonda.
The broken Campense obelisk is excavated, restored and raised in Piazza Montecitorio.
The Ara Pacis is recovered and recomposed while the Mausoleum district is radically demolished and rebuilt.
The Ara Pacis museum and renewed Piazza Augusto Imperatore create a new public frame for the Augustan monuments.
Before your visit
The Pantheon is both a state monument and an active basilica. Buy only through the official Musei Italiani channel or on-site systems, and recheck service restrictions.
Basilica of Neptune, Arco della Ciambella and Hadrianeum can be read from public space; museum or exceptional interior access follows different schedules.
Horologium fragments lie below modern buildings and are not a continuously open archaeological attraction. Confirm any visit with the responsible institution.
The official monument page has reported suspended interior visits since June 2022. The renewed square remains publicly legible even when the tomb is closed.
The Pantheon quarter and Augustan northern Campus Martius are walkable in one day, but the Ara Pacis deserves museum time rather than a rushed final stop.
Oculus light changes through the day, while ancient pavements sit below current streets. Weather, worship and crowding materially alter how these sites can be read.
Method and sources
The guide uses official institutional and monument sources current to 27 August 2026. It distinguishes Agrippa's first Pantheon from Hadrian's surviving building, the Basilica of Neptune from the baths, ancient obelisks from their modern settings, excavated Horologium evidence from disputed total reconstructions, and the original Ara Pacis fragments from both twentieth-century recomposition and the current museum.
All ten images are original Merlintravel editorial watercolours based on documented present-day conditions. They are illustrations, not substitutes for archaeological plans. Opening hours, tickets, accessible routes, temporary exhibitions and conservation work can change; consult the linked official pages shortly before visiting.