Rome Opens Hidden 2,000-Year-Old Mosaic to Public for First Time
Rome has opened a 2,000-year-old underground mosaic hall to the public for the first time.
The first visitors walked into the site beneath the Baths of Trajan in Rome on 12 and 13 September 2026, according to The Art Newspaper. It is a short walk from the Colosseum, under the Oppian Hill. For now entry is in small weekend groups of 15.
The space holds two works. They are called the “Painted City” fresco, a painting made directly on wet plaster, and the “Muse and the Philosopher” mosaic, a picture made from tiny cubes of stone and glass.
The mosaic is huge. It stands ten metres high and runs for 16 metres along a wall. Archaeologist Francesco Pacetti has estimated it is the largest wall mosaic yet found from the Roman world, and said excavators are still digging to find where it ends.
What you see is dense and strange. The mosaic spreads across four levels, with figures and buildings stacked one above another. Opposite it, the fresco shows a walled port city seen from above, with defensive walls, towers and blocks of houses.
The fresco measures more than ten square metres, according to ANSA. Italian reports have noted its use of perspective to suggest depth, long before the Renaissance architect Filippo Brunelleschi set out the rules in the 1400s.
Both works were found in the 1990s in a buried gallery below the baths. They are thought to date from the first century. Rome mayor Roberto Gualtieri said the fresco was likely made in the Neronian era of 54-68AD or the Flavian era of 69-96AD, before the Baths of Trajan were opened in 109AD.
The mosaic once decorated a large hall looking onto a nymphaeum, an ornamental fountain building popular with wealthy Romans.
What makes this stand out is how hidden it stayed. The decoration survived because later imperial building simply covered it over.
Visits will expand from 2 October, running Friday to Sunday. The early tours on 12 and 13 September were free guided visits in Italian by reservation, according to ANSA’s travel service.
The opening follows the launch earlier in September of a new on-site museum for the Baths of Trajan. Restoration of the complex was carried out under the PNRR-Caput Mundi programme, a €500 million project funded by the European Union.
