One of the interesting things about archaeology is how it tends to emphasize the lavish living spaces of the rich. But what supported all that excess? (Or--who wants to visit a big clot of miserable huts or slave quarters?)
There are interesting sites which feature the function of working people and/or slaves. For example, the recent restoration of the tunnels under the Baths of Caracalla offers a rare glimpse into the slave machinery needed to keep the baths functioning.
"An army of hundreds of slaves kept firmly out of sight of bathers scurried along the tunnels feeding 50 ovens with tonnes of wood a day to heat water surging through a network of underground channels that arrived via aqueduct from a source 100km away. Below that, massive sewers, which are now being explored by speleologists, flowed towards the Tiber." ~ Restoration of Roman tunnels gives a slave's eye view of Caracalla baths
The bath complex, located just outside central Rome, is larger than modern spas, and used a quite a bit of wood, as you might expect. The tunnels offer evidence of a traffic system for carts carrying tons of logs. Imagine the stress on nearby forests from the feeding of all the Roman baths.
According to the interesting article linked above, the tunnels will be open for viewing on December 21.