2. Avoid equilateral shapes for piazzas designed to be socially lively
Piazzas are often intended to be places that knit neighbourhoods together through serving as a centre for sociable activities. On the face of it, web this is problematic as piazzas by their nature as open urban spaces may have a much lower level of energy than the streets which feed into it. After all, streets are strongly directional, with almost everyone moving in one direction or its reverse in a typically relatively narrow and constrained space. The large numbers of people moving in the same direction visually ‘reinforce’ the street’s kinetic energy, and this paradoxically may also be reinforced by the people moving in the opposite direction due to the risk of collisions.
However, this sense of movement and energy is greatly reduced when we move from a street to a piazza — pedestrians can move in a much wider gamut of directions so that they no longer reinforce each other’s movement as powerfully, and people tend to linger in piazzas rather than move energetically. Relative to the streets we enter from, the piazzas that are so often intended to be places of great activity are calm in the same way that water in a narrow river may move with great force but when it reaches a wider part of the river may move almost imperceptibly.
This is important because key ingredients of many lively piazzas are the ability to people-watch and the provision of seating within close proximity to a stream of passers-by to enable people to clearly observe them in comfort. Since both seating provision and the human eye have limits, it’s desirable a piazza to have some kind of directionality: a shape that implies certain directions are more important than others and therefore gives cues to movement. A piazza with directionality, all things being equal, is more likely to concentrate pedestrians in relatively narrower streams than piazzas that are equilateral. If the routes of passers-by are predictable and within narrow bands then seating for the purposes of people-watching can be provided at a distance that both allows people-watchers to perceive the visual details of passers-by and allows those passers-by to be both physically unimpeded and not feeling they are running a gauntlet of observers.
It’s desirable for socially lively piazzas to have some directionality in their design, then, and upon examining piazzas from around the world we’ll find that lively squares are very rarely — well — square. I can think of quite a few successful square-shaped piazzas, for example many in London and Place des Vosges in Paris, but these are residential squares, where tranquility is often aimed at.
In residential areas it may well be a good idea for piazzas to be equilateral, then. However, where the piazzas occur at the junctions of major roads making them easily accessible from many parts of the city — as in Wren’s plan — then we might guess that the piazzas are intended to be intensively used focal points rather than places of tranquility and relaxation. If it were Wren’s intention to make his piazzas socially lively (and it may well not have been; it may have just been swift and efficient movement across the city) it would therefore undermine the intended function of the piazzas for them to be equilateral in shape.
However a major feature of Wren’s plan are equilateral piazzas at the junctions of radiating major roads and at the cores of their districts: two circles and an only slightly deformed hexagon. The lack of directionality could be in part remedied by some dominating piece of architecture that makes a particular side of the piazza seem more important — and which attract a predictable stream of people to it — but none of these equilateral piazzas have any such building on them, despite Wren placing churches in fairly close proximity to them. These piazzas may not have become ideal places for social interaction, then. Social engagement is, to stress, not the sole criterion of successful piazzas, and other types of piazzas may be desirable depending on the circumstances.
3. Create ‘destination’ piazzas rather than simply ‘thoroughfare’ piazzas
Despite the importance of directionality in piazzas, it’s important to note that a piazza is not simply a ‘street with good people-watching facilities’, or even ‘just a wide street’. A piazza can also be what streets almost by definition cannot be: primarily a destination rather than a thoroughfare, a place where people might be going to rather than simply pass through.
Where this is desired, one way to encourage it through the design of the piazza is to employ a variety of devices to conceal or draw attention of those within the piazza away from the streets that lead to it, so that although the pedestrian is naturally well aware that various streets feed into the piazza, she cannot see out of more than one of them at a time. The more destinations a piazza seems to offer itself as a conduit to, the less of a destination it becomes itself.
(Of course, this objective may have to be balanced with the objective of providing directionality, but equally the less you can see out of any piazza the more cues as to the more important direction may be needed.)
Camillo Sitte recommended a ‘turbine wheel’ configuration for the streets reaching the piazza, meaning that the piazza is not reached by streets at right angles but by those at an angle. The effect of this is that from most positions in the piazza you can only see out it through one of the square’s exit streets, making it seem an almost enclosed space. This can have the effect of making it seem a destination rather than a thoroughfare. However it should be noted that to the extent it does, and depending on how the various exit streets relate to each other, through traffic — fast moving traffic, at least — will be inhibited, and this may or may not be a desirable result.
Another means of encouraging this sense of a destination (with a similar potential drawback) is to make streets that roughly continue each side of the piazza non-aligned so that each street points at a building rather than the continuation of the street.
One example of this is in Piazza di Spagna in Rome, which contains the Spanish Steps. Of the three main streets that approach the piazza from the west, the sightlines across the piazza are blocked: at the north (Via delle Carrozze) by a building due to the non-aligned continuation of the street and the line of trees (an unusual addition to an Italian piazza); at the south (Via Borgognona) by another building. The continuation of the middle street (Via dei Condotti) is also effectively blocked simply due to the multi-storey change of level up the Spanish Steps. This, of course, has the effect that from the top of the Spanish steps you can see right down Via dei Condotti, and thus from that point the space ‘leaks’. However, an exception to the general advice that space should not leak — that the illusion that the piazza forms an intact entity, is when a part of the piazza behaves like a viewing platform. Few people climb a platform in order to gaze at a brick wall in quite close proximity, for example, and the direct view down one of Rome’s most fashionable streets is a suitable vista for such a good vantage point.
Other means include blocking views through the use of landmarks as does the Baptistery (b) from the centre of the piazza in Camillo Sitte’s illustration below…
…using landmarks as focal points…
… or spanning the street so as to provide some continuity with adjoining parts of the piazza.
Wren’s plan for London includes a large number of ‘leaky’ piazzas. In particular, the equilateral piazzas mentioned earlier all offer multiple very direct views out of the piazza to destinations far away. In addition, the triangular piazza in front of St. Paul’s offers wide vistas of the eastern sections of the city via the two southerly arterial streets either side of the Cathedral.
In practice, the Cathedral’s dominance is likely to somewhat reduce the apparent leakiness through attracting the pedestrian’s gaze to itself, in a similar way to the flashing adverts of New York’s Times Square distracts from the leaky canyons either side, but the design is still likely to render the piazzas rather less socially lively than they otherwise could be.