The marks, which are sandwiched between towers once used to scout for armies and to allow archers and other artillery-throwers to fend off enemy incursions, are arrayed in a way that suggests they may have been left by a repeating dart-thrower called a polybolos.
There were variations in the chemical composition of the deposits, indicating the replacement of boilers for heating water and a renewal of water pipes in the infrastructure of Pompeii, particularly during the time period when modifications were being made to the Republican baths. The results for the Republican baths' heated pools, for instance, showed clear contamination from human activity, specifically human waste (sweat, sebum, urine, or bathing oil), which suggests the water wasn't changed regularly.
On a map, Pompeii's Villa of the Mysteries looks like an afterthought-a small, distant square, as far away as possible from the ancient city's amphitheatre, where the action was. But the suburban villa, which dates to the second century BC, is the red-hot centre for many who make the pilgrimage here. Its room of celebrated frescoes contains some of the best-known and best-preserved examples of Ancient Roman art.