The Terme Maschili were the men's section of the Terme del Foro (Forum Baths). Note the ancient latrine to the left of the entrance before you step into the apodyterium (changing room), complete with bench for waiting patrons and a nifty wall shelf for sandal and toga storage.
While those after a bracing soak would pop into the frigidarium (cold bath) to the left, the less stoic headed straight into the tepadarium (tepid bath) to the right. The sunken mosaic floor here is testament to the seismic activity preceding Mt Vesuvius' catastrophic eruption. Beyond this room lies the caldarium (hot bath), as well as an exercise area.