A painted port city hidden underground for centuries is finally visible again in Rome. Discovered during excavations in the 1990s, the vast fresco and accompanying mosaic beneath the Baths of Trajan have now been restored and opened to small groups after decades of conservation.
The Discovery
Authorities in Rome have unveiled what they describe as the largest known fresco and mosaic complex of ancient Rome, giving the public its first opportunity to see the remarkable works since their discovery.
The fresco and mosaic were found during archaeological excavations in the 1990s beneath the Baths of Trajan, on Oppio Hill near the Colosseum.
Rome Mayor Roberto Gualtieri presented the restored works on 8 September, describing the fresco as an extraordinary surviving example of ancient Roman wall painting.
Known as the “Painted City”, the fresco depicts a walled port settlement viewed from above.
Its surviving colours include blue and terracotta tones, although centuries underground have left them faded.
The scene contains buildings, a theatre, a temple, public squares and towers, creating an unusually detailed representation of an ancient urban landscape.
Yet one major question remains unanswered.
The city shown in the fresco has not been identified.
Rome's cultural superintendent, Claudio Parisi Presicce, said its grandeur and state of preservation suggest that the painted settlement must have been particularly well known.
For now, archaeologists can study the city's architecture and layout without being able to attach a definite historical name to it.
What Archaeologists Found
The newly opened complex contains two major decorated works: the “Painted City” fresco and the “Great Mosaic.”
The fresco's bird's-eye representation of a fortified port city is its most striking feature.
The image appears to combine architectural detail with an unusual overhead perspective, allowing viewers to see the organisation of the settlement rather than simply individual buildings.
Among the visible structures are a theatre, temple, towers and public piazzas.
The mosaic provides a different visual experience.
It measures approximately 15 metres high and contains elaborately decorated columns, architectural features and human figures arranged across four levels.
The upper sections feature people depicted at close range, with scenes that have an almost theatrical character.
Lower down, the composition shifts towards views of the port city's overall arrangement from above.
Together, the fresco and mosaic create an unusually extensive record of urban and architectural imagery from ancient Rome.
Their survival is particularly notable because both works remained underground for centuries.
Historical Background
The artworks were discovered beneath the Baths of Trajan, one of the most ambitious monumental complexes of imperial Rome.
Emperor Trajan dedicated the baths in AD 109, and the complex covered approximately six hectares, or around 15 acres.
At the time, the Baths of Trajan were the largest bath complex in the world.
The enormous facility incorporated an earlier bathing complex associated with the Domus Aurea, the vast palace complex constructed under Emperor Nero.
The Baths of Trajan were also designed differently from the earlier complex, with their layout taking greater advantage of water temperatures to improve the experience of bathers.
But bathing was only one part of life within such a monumental public complex.
The area now being opened also includes a large semicircular upper-level structure identified by archaeologists as a “library.”
Researchers believe it formed part of the baths and provided space for cultural activities alongside exercise and bathing.
This helps place the newly accessible artworks within a broader environment in which physical recreation, architecture and intellectual pursuits existed side by side.
Scientific Analysis
The restoration was designed not only to make the fresco and mosaic visible but also to protect their fragile surfaces.
Conservators removed surface deposits that had accumulated over time and used techniques intended to improve visibility while maintaining the surviving decoration.
The work also included consolidating the grouting to help stabilise the decorated surfaces.
The restoration team faces another challenge now that visitors are being admitted.
The artworks had remained in a controlled underground environment for decades. Increased humidity and other climatic effects caused by visitor access could affect the fragile materials.
For that reason, the opening is initially being conducted as a trial period, with groups limited to 15 people and access taking place on weekends.
Officials will monitor how the artworks respond before considering broader public access.
The approach reflects a central problem in archaeological conservation: making fragile discoveries accessible while ensuring that exposure to modern environmental conditions does not accelerate their deterioration.
Why This Discovery Matters
The importance of the Painted City extends beyond its size.
Few surviving Roman artworks offer such a detailed representation of a complete urban environment from an elevated perspective.
The depiction appears to show not merely individual buildings but an entire port settlement, including its fortifications, public spaces and monumental structures.
That makes the unidentified city potentially valuable for understanding how Romans imagined and represented urban landscapes.
The Great Mosaic adds another layer, combining architecture, figures and different scales of representation across four levels.
The two works together may provide evidence about artistic conventions, architectural imagery and the ways ancient Roman artists constructed complex scenes.
Their location beneath the Baths of Trajan also matters.
The discovery links large-scale decorative art with one of imperial Rome's greatest public complexes.
Why did Roman artists choose to depict this particular port city, and could the details eventually reveal where it was?
Until the city is identified, that question remains one of the most intriguing aspects of the discovery.
What’s Next?
For the first time, members of the public can see the restored artworks, but access is deliberately restricted.
Small groups of 15 are being admitted during weekend visits as authorities assess the effects of increased humidity and other environmental changes.
The results of that monitoring will help determine whether wider access can be permitted.
Meanwhile, archaeological and conservation research can continue on the imagery itself.
The identity of the painted city remains unresolved, making architectural details particularly important.
Researchers may be able to compare the buildings, towers, theatre, temple and port layout with known ancient settlements.
Further analysis of the mosaic could also help clarify the meaning and relationships of the figures and architectural scenes spread across its four levels.
The broader complex, including the possible library, adds another opportunity to understand how the Baths of Trajan functioned as a centre for bathing, exercise and cultural activity.
Conclusion
After remaining hidden for decades, the Painted City fresco and Great Mosaic beneath Rome's Baths of Trajan are finally accessible to visitors.
The vast fresco depicts an unidentified walled port city from above, complete with buildings, towers, a theatre, temple and public spaces. Nearby, the 15-metre-high mosaic combines architectural elements and human figures across four distinct levels.
Their restoration has made public access possible, but carefully controlled opening is essential because the fragile works must be protected from changes in humidity and climate.
The biggest mystery remains the city itself.
Until its identity is established, the Painted City preserves an extraordinary Roman urban landscape whose original name has been lost.
FAQ
Where were the Roman fresco and mosaic discovered?
They were discovered during excavations in the 1990s beneath the Baths of Trajan on Oppio Hill near the Colosseum in Rome.
What does the Painted City fresco show?
The fresco depicts a walled port city from a bird's-eye perspective, including buildings, a theatre, temple, public piazzas and towers.
How large is the Great Mosaic?
The mosaic measures approximately 15 metres high and contains architectural elements, decorated columns and human figures arranged across four levels.
Can the public visit the artworks?
Yes, but access is initially restricted to groups of 15 during weekend visits. Authorities are monitoring environmental conditions before deciding whether to expand public access.
