An unusual Roman mosaic showing the plan of the building (or rather its fragments in two pieces), probably public or private baths. The mosaic probably dates from the middle of the 3rd century CE.
The various elements of the building are depicted in coloured tesserae:
the rooms are white
walls are marked in yellow with grey outline
water tanks (baths and pools) – arranged from green stones
water channels – blue colour.
Some markings are unclear. For example, what do Roman numerals mean? Is that the room number? Designation of its function? Or maybe dimensions? Other red symbols are unclear: some seem to mark openings in the walls (windows?), Others maybe heating cable outlet?
I have seen many mosaics before, but I have never come across such a detailed “plan” before.
The mosaic was found in Rome, near Termini Station. I took the photo at the Centrale Montemartini museum during a temporary exhibition. It is permanently part of the collection of the Capitoline Museums, but I do not know if, apart from the temporary exhibition, it is open to visitors.