We should note that all of these places of thermal extremes (Finnish saunas, Japanese hot baths, American beaches and mountains) have their opposites close at hand. There are possibly two reasons for having the extremes right next to each other.
The first is physiological: the availability of extremes ensures that we can move from one to the other to maintain a thermal balance.
The second might be termed aesthetic: the experience of each extreme is made more acute by contrast to the other.
Works of art which have great life often have intense contrast within: rough/smooth, solid/void, loud/silent, empty/full. It is the difference between opposites which gives birth to something. Contrast is what often gives other principles their degree of life – the intensity of the boundary, the markedness of the alternating repetition.
Contrast strengthens centers by making each a deeper entity of itself, and thereby giving deeper meaning to both. It is, at its simplest, what allows us to differentiate. But meaningless contrast remains meaningless. It is only when centers are actively, mutually, and meaningfully composed that it acts to deepen the whole.
In Architecture Without Architects, Bernard Rudofsky documented the ways in which most cities were mostly built by improvisation, following no consistent formal design. Building was added to building, street to street, their forms adapting to different site conditions in the process of extension.
Rudofsky thought that this hidden order is how most settlements of poor people develop and that the work of improvising street order attaches people to their communities, whereas 'renewal' projects, which may provide a cleaner street, pretty houses, and large shops, give the inhabitants no way to mark their presence on the space.