series of rooms that offered communal bathing in three temperatures, with varying amenities that might include an exercise and weight-training room, sauna, exfoliation spa (where oils were massaged into the skin and scraped from the body with a strigil), ball court, or outdoor swimming pool. Baths had hypocaust heating: the floors were suspended over hot-air channels that circulated warmth. Mixed nude bathing was not unusual in the early Empire, though some baths may have offered separate facilities or hours for men and women. Public baths were a part of urban culture throughout the provinces, but in the late 4th century, individual tubs began to replace communal bathing. Christians were advised to go to the baths for health and cleanliness, not pleasure, but to avoid the games (ludi), which were part of religious festivals they considered "pagan". Tertullian says that otherwise Christians not only availed themselves of the baths, but participated fully in commerce and society. Rich families from Rome usually had two or more houses, a townhouse (domus, plural domūs) and at least one luxury home (villa) outside the city. The domus was a privately owned single-family house, and might be furnished with a private bath (balneum), but it was not a place to retreat from public life. Although some neighbourhoods of Rome show a higher concentration of well-to-do houses, the rich did not live in segregated enclaves. Their houses were meant to be visible and accessible. The atrium served as a reception hall in which the paterfamilias (head of household) met with clients every morning, from wealthy friends to poorer dependents who received charity. It was also a centre of family religious rites, containing a shrine and the images of family ancestors. The houses were located on busy public roads, and ground-level spaces facing the street were often rented out as shops (tabernae). In addition to a kitchen garden—windowboxes might substitute in the insulae—townhouses typically enclosed a peristyle garden that brought a tract of nature, made orderly, within walls. The villa by contrast was an escape from the bustle of the city, and in literature represents a lifestyle that balances the civilized pursuit of intellectual and artistic interests (otium) with an appreciation of nature and the agricultural cycle. Ideally a villa commanded a view or vista, carefully framed by the architectural design. It might be located on a working estate, or in a "resort town" situated on the seacoast,