Rome Opens the Restored Painted City and Great Mosaic at the Baths of Trajan

Rome has restored the first-century Painted City fresco and Great Mosaic beneath the Baths of Trajan, adding a newly excavated port-city band to the mosaic and preparing the first tightly limited public visits. The official measurements also correct a misleading figure in early coverage: 15 meters describes the surviving mosaic wall’s length, not its height.

 
 

Two Roman Pictures, in Two Earlier Buildings

The Painted City and the Great Mosaic are often presented as a pair, but they are not a single 15-meter artwork. Rome’s official historical dossier locates the fresco near the end of a roughly 70-meter underground gallery and the mosaic about halfway along it, in a different room. Both decorated structures from the second half of the first century AD, before the Baths of Trajan opened in AD 109.

The Painted City is about 10 square meters. It occupied the plastered façade between two arches and shows a walled port from an elevated viewpoint: streets, housing blocks, a theater, a temple, a colonnaded court, towers, water, and a fortified basin are organized in perspective. For readers familiar with fresco painting chiefly through interior decoration, its position on a monumental façade is as important as its bird’s-eye composition. The identity of the city remains unresolved.

The Great Mosaic is a much larger architectural program. It covered the east and south walls of a hall adjoining a nymphaeum. The surviving walls extend approximately 15 meters and 10 meters respectively; the mosaic now visible rises for about five meters. Its main scheme resembles a theatrical scaenae frons, divided into two registers of perspective architecture, garlanded columns, vegetation, Dionysian emblems, statues, and human figures. That makes it an unusually ambitious example of a Roman wall mosaic, not a mosaic pavement.

The dimensional distinction matters because the Associated Press report published September 8 describes the mosaic as roughly 15 meters high. Rome’s records assign that figure to the length of the east wall. They give about five meters as the height so far exposed and estimate, from the new excavation, that the room’s walls originally reached about 12 meters. The official evidence therefore supports “15 meters long,” not “15 meters high.”

The newly uncovered lower band makes the vertical arrangement clearer. Beneath the theatrical architecture, it shows buildings probably facing the sea, linked by archaeologists to the motif of maritime villas. Below that band are traces of large marble revetment and a marble-lined niche about 2.2 meters high. The floor has not been reached. Together, those finds show that the room combined a distant marine panorama, staged architecture, and costly marble rather than repeating one continuous city view from top to bottom.

 

An exedra at the Baths of Trajan in Rome, photographed by Rabax63 and hosted by Wikimedia Commons, under the Creative Commons Attribution-Share Alike 4.0 International license; cropped.

 
 

How Trajan’s Baths Preserved Older Art

The fresco and mosaic are at the Baths of Trajan, but they were not made for the bath complex. The distinction is easy to lose because the later building is the reason they survived. Trajan’s architects buried or incorporated earlier rooms while creating a six-hectare terrace on the Oppian Hill. The long gallery supported the portico in front of the southwestern exedra, turning the older decorated structures into foundations.

That stratigraphy also separates discovery from the current news. Rome did not find both works in 2026. Excavation proceeded in stages, and the latest project added evidence to objects known for decades.

Date	What happened
1990–1992	Excavators exposed remains of an 18th-century gunpowder works in the gallery.
1997–1999	Work revealed the brick façade and the Painted City fresco.
2010–2014	Campaigns established the scale and two-wall setting of the Great Mosaic.
Apr. 24, 2025–June 15, 2026	The Caput Mundi restoration and access project ran for nearly 14 months.
Sept. 8, 2026	Rome unveiled the restored ensemble and announced controlled visits.
Sept. 12, 2026	The first trial weekend is scheduled to begin.

The latest intervention went beyond cleaning the images. A new walkway bridges sections of the underground gallery above the mosaic room, while lighting, visitor reception, and an upper-to-lower mechanical connection reshape access. Structural load tests were carried out on the vault beneath the exedra. Deeper excavation exposed the additional mosaic band, the marble zone, and the niche that now support the 12-meter reconstruction of the room.

The Baths of Trajan in 2013, before the latest restoration project. Photograph: Sailko, CC BY-SA 3.0.

 
 

Restoration Comes With a Strict Visitor Cap

According to Rome’s technical account, conservators used a preventive biocide treatment, removed surface deposits, consolidated unstable areas, and made necessary fills. Those measures improved legibility without turning the faded blue and terracotta passages reported at the unveiling into newly painted surfaces.

Public access is deliberately a conservation trial. AP reported that the small-group arrangement is intended to test how the works respond to increased humidity and other climatic effects. Rome’s own notice describes the broader objective as monitoring the impact of human presence on the delicate decorations. Neither source promises that the cap will be lifted.

Rome’s booking page sets a limit of 15 participants per weekend tour. Six Italian-language tours are scheduled on each open Saturday and Sunday, with no more than 15 people in a slot—at most 90 ordinary visitors per day. Rome’s current visitor page lists the September dates as sold out. From October through December 27, Saturdays and Sundays are assigned to individual visitors, while Fridays are reserved for schools and groups with their own guides. The guided visit is free, but admission is charged from October; the listed full nonresident ticket is €7.50.

A subterranean environment helped preserve the images after Trajan’s builders covered the earlier structures. The same enclosure now makes moisture, airflow, and repeated human presence central to whether the public can continue seeing them.

 
 

The Mosaic Is 15 Meters Long, Not 15 Meters High

The official dimensions correct AP’s 15-meter-high description: the east mosaic wall is about 15 meters long, about five meters of height is exposed, and the room is reconstructed at approximately 12 meters high.