these places, like nesting. Time breeds attachment to place.
The cities we know today, outside the European orbit, are fast moving; the urbanisation of Asia, Latin America and Africa has occurred in decades, not centuries. The drivers of fast time – developers, investors, national actors – want their cities to be closed in form; that is, to be quantifiable, determinate, balanced and well-integrated. The investor knows what he or she is getting.
If we want urban development to be open, we cannot counter these forces simply by saying ‘slow down’ or ‘wait’. Jacobs’s Burkian sense of time, accompanied by her championing of small businesses, hasn’t much traction in the face of today’s political economy. Instead, resistance to the closing of the city makes countervailing designs all the more important.
In my own thinking, I’ve wondered what kinds of physical forms might resist the closed city and empower the open. The plans presented by Pablo Sendra in this book explore the physical infrastructure which might do so. Above ground, there are three kinds of ‘urban DNA’ configurations that can be deployed in a situation of rapid, massive urban development. These three forms in an open city are 1. passage territories; 2. incomplete objects; and 3. nonlinear narratives.
Passage territories
I’d like to describe in some detail the experience of passing through different territories of the city, both because that act of passage is how we know the city as a whole, and also because planners and architects have such difficulty designing the experience of passage from place to place. I’ll start with walls, which seem to be structures inhibiting passage, and then explore some of the ways edges of urban territory function like walls.
Walls
The wall would seem an unlikely choice; it is an urban construction which literally closes in a city. Until the invention of artillery, people sheltered behind walls when attacked; the gates in walls also served to regulate commerce coming into cities, often being the point at which taxes were collected. Massive medieval walls such as those surviving in Aix-en-Provence or Rome furnish a perhaps misleading general picture; ancient Greek walls were lower and thinner. But we also mis-imagine how those medieval walls themselves functioned.
Though they shut closed, they also served as sites for unregulated development in the city: houses were built on both sides of medieval town walls; informal commerce with black-market or untaxed goods sprung up nestled against them; the zone of the wall was where heretics, foreign exiles and other misfits tended to gravitate, again far from the controls of the centre. These spaces would have attracted the anarchic Jane Jacobs.
But they were also sites which might have suited her organically focused temperament. These walls functioned much like cell membranes, both porous and resistant. That dual function of the membrane is, I believe, an important principle for visualising modern urban living forms. Whenever we construct a barrier, we must equally ensure the barrier is porous; the distinction between inside and outside has to be breachable, if not ambiguous.
The typical contemporary use of plate glass for walls doesn’t do this; true, on the street you see what’s inside the building, but you can’t touch, smell, or hear anything within; the plates are usually rigidly fixed so that there is only one, regulated, entrance within. The result is that nothing much develops on either side of these transparent walls: as in Mies van der Rohe’s Seagram Building in New York or Norman Foster’s new London City Hall, you have dead space on both sides of the wall; life in the building does not accumulate here. By contrast, nineteenth-century architect Louis Sullivan used much more primitive forms of plate glass more flexibly, as invitations to gather, to enter a building or to dwell at its edge; his plate glass panels function as porous walls. This contrast in plate glass design brings out one current failure of imagination in using a modern material so that it has a sociable effect.
The idea of a cellular wall, which is both resistant and porous, can be extended from single buildings to the zones at which the different communities of a city meet.
Borders
Ecologists like Stephen Jay Gould draw our attention to an important distinction in the natural world, that between boundaries and borders. The boundary is an edge where things end; the border is an edge where different groups interact. In natural ecologies, borders are the places where organisms become more inter-active, due to the meeting of different species or physical conditions. For instance, the shoreline of a lake, where the water meets solid land, is an active zone of exchange; here organisms find and feed off other organisms. The same is true of temperature layers within a lake: where layer meets layer defines the zone of most intense biological activity. Not surprisingly, it is also at the borderline where the work of natural selection is most intense, whereas the boundary is guarded territory, as established by prides of lions or packs of wolves. The boundary establishes closure, whereas the border functions more like a medieval wall. The border is a liminal space.
In the realm of human culture, territories consist similarly of boundaries and borders – in cities, most simply, there is a contrast between gated communities and complex, open streets. But the distinction cuts deeper in urban planning.
When we imagine where the life of a community is to be found, we usually look for it in the centre of a community; when we want to strengthen community life, we try to intensify life at the centre. The edge condition is seen to be more inert, and indeed modern planning practices, such as sealing the edges of communities with highways, create rigid boundaries lacking any porosity. But neglect of the edge condition – boundary thinking, if you like – means that exchange between different racial, ethnic, or class communities is diminished. By privileging the centre, we thus weaken the complex interactions necessary to join up the different human groups the city contains.
Let me give as an example a failure in my own planning practice. Some years ago, I was involved in a plan to create a market to serve the Hispanic community in Spanish Harlem in New York. This community, one of the poorest in the city, lies above 96th Street on Manhattan’s Upper East Side. Just below 96th Street, in an abrupt shift, lies one of the richest communities in the world, running from 96th down to 59th Street, comparable to Mayfair in London or the 7th Arrondissement in Paris. Accordingly, 96th Street itself could function either as a boundary or a border. We planners chose to locate La Marqueta in the very centre of Spanish Harlem, twenty blocks away, and to regard 96th Street as a dead edge where nothing much happens. We made the wrong decision. Had we located the market on 96th Street, we might have encouraged activity which brought the rich and the poor into some daily commercial contact. Wiser planners have since learned from our mistake and on the West Side of Manhattan sought to locate new community resources at the edges between communities, in order, as it were, to open the gates between different racial and economic collectivities. Our prioritisation of the centre proved isolating; their understanding of the value of the edge and border has proved integrating.
I don’t mean to paint a Panglossian picture of such ventures in planning: opening up borders means people of different strengths are exposed to competition. Borders can serve as tense rather than friendly sites of exchange – evoking some of the predatory quality of border conditions in natural ecologies. But taking that risk, which planners are now doing under more explosive conditions in Beirut and in Nicosia, is the only way, I believe, in which we can create conditions for a socially sustained collective life in cities; ultimately, isolation is not a true guarantor of civil order.
The porous wall and the edge as border create essential physical elements for an open system in cities. Both porous walls and borders create liminal space – that is, space at the limits of control, limits which permit the appearance of things, acts and persons unforeseen yet focused and sited. Biological psychologist Lionel Festinger once characterised such liminal spaces as defining the importance of ‘peripheral vision’; sociologically and in an urbanistic sense, these sites operate differently
