The Museion under the Baths of Trajan in Rome yielded a beautiful fresco of a city. We know that the structure it decorated dates to between AD 64 and 109 (more here). The fresco was found in 1997, and the archaeologists believe it's a view of Rome. Based on their identification, I tried to work out where in Rome it depicted.
here),, thinking maybe it still existed a century later. That's when I ran into problems. The main theatres of Rome - Pompey, Marcellus, Balbus and Domitian - existed at the right date, but were all in the Campus Martius, so outside the walls. This structure is clearly inside them. It seems to be covered and small, which suggests it could be one of the many temporary wooden theatres which were still erected during the Empire, usually for pantomimes, or more likely a smaller Odeon for musical performances. And frankly if the fresco is to scale, then it's a very small theatre ... Although it matches up best on the Marble Plan with the theatre of Pompey which had a large portico in front of it, as can be seen below:
The problem is that there are two gates in the fresco (blue and green circled) and the whole area seems to be surrounded by walls (in red).
So the fresco depicts a city, and it was found in Rome ... but does it actually represent Rome or another idealised city? Perhaps a depiction of Romulus' idealised city of Rome? The closest parallel I can suggest is the 6th century Byzantine Madaba mosaic map, which depicted the city of Jerusalem, as seen here.
I'd also like to highlight the marble map dating to the 1st century AD in the museum at Orange, which tends to get overlooked (source) but depicts the region.
After extensive discussions - Judith suggested Antioch - I realised that the Rome fresco was published here:
E. La Rocca, 2000, L’affresco con veduta di città dal Colle Oppio, in E. Fentress (ed.), Romanization and the City: Creation, Transformations, and Failures, (JRA Suppl. 38): 57-71.
Prof La Rocca feels that "shows a fortified city with a harbour, a theatre and temple, a forum and a small hill adorned with a Tuscan temple" (source) and whilst he discusses it in the context of other such ancient views, he does not claim it is Rome.