The DNA of a City

Every livable city has its own unique character that is expressed in its architecture and arrangement of streets and open places. It is not inappropriate to propose the metaphor that the livable city, like every living thing, has a genetic code, or a DNA structure.

Santa FeThe DNA of a city is expressed in those architectural and spatial characteristics best loved by the city’s inhabitants that contribute most to its sense of identity. These may consist of certain building materials and colours, a typical arrangement of scale and architectural forms, building lot size, roof lines, scale of public and semi-public spaces.

In order to fit into the urban context, new buildings must respect this “genetic” code, reflecting at least some of the existing patterns, or interpreting them in a contemporary idiom.

As there used to be a consensus about a community’s values, so was there also a consensus about what materials, architectural and spatial forms represented the unique character of one’s city.

Each person in the community recognized and understood this unique character, and worked within its constraints, although there was still considerable variation possible, in choice of colours and materials, detailing, degree of elegance, as well as in the architectural expression of the city’s varied functions.

This consensus, which the playwright Peter Schaffer calls the “communal eye”, has been lost in many places, but there are still many citizens who are intuitively able to recognize their city’s unique character, and can identify appropriate and inappropriate development. There are architects who design context-specific buildings exemplifying the best of the city’s heritage. And mechanisms exist to reinforce a city’s special qualities.

One of these, for example, is the historic heritage survey, which chronicles a city’s architectural legacy and the cultural significance associated with some of its buildings. In this connection too, the efforts of such leaders as Prince Charles are important in raising critical awareness, and the community’s sense of responsibility for their city.

Some developers and architects argue that the individual city’s identity, and the community’s recognition of the unique character of their city no longer exist, and that, therefore, they are not obliged to consider the city’s past identity in their projects. The results of this view can be seen in almost every city in the world.

In many North American and some European cities, architects and developers have been allowed to build structures that bear no relationship either to surrounding buildings, or the city’s character and tradition. Buildings compete for attention but do not pay attention to each other. The dialogue among building is too often characterized by fragmentation and discontinuity, and the collage of buildings and public spaces creates a profound sense of anomic dissociation.

We internalize the built environment. But we are gradually eroding our urban sense of identity. A true sense of identity can only be maintained through a dialogue between community and architects, through community participation programs, and the development of design guidelines sensitive to each city’s specific historic heritage.

Through public discourse we need to develop again this “communal eye”, this vision of the characteristics of the buildings and places that are valued, that give a sense of place, identity and meaning to the city. And to facilitate this, of course, we need to create public spaces, streets and squares that are hospitable to social contact, connection and civic dialogue.

The architecture of the city embodies the city’s memory. When a building is destroyed, then the memories that each individual had in connection with that building can no longer be passed on to others. And when too much of the original texture of the city is replaced by inappropriate structures, our own memories fade. 

If too much of the architectural heritage is destroyed, the city’s communal memory of its unique identity is violated, making it susceptible to social problems.

But even a city badly damaged architecturally can recover if the citizens understand its genetic code, and define developmental goals based on this code.

Architectural Structure and Fabric

Santa BarbaraFor an organism, the DNA contains instructions on such characteristics as colour of eyes, or hair: for a city on such characteristics as building materials, building colours, roof shapes, and size of windows.

These transmitted characteristics vary in small ways, within a limited range, from individual to individual, and from generation to generation, without harm to the individual or to the society. Indeed, these variations are essential to our sense of identity as individuals.

Similarly, the physical characteristics of the city should vary within a limited range, from building to building, and from city to city. It is these small and subtle variations on architectural themes that impart a sense of identity to the street or the city...

Those cities that recognize their unique character are able to develop clear design guidelines for future development, specifying what building materials, palette of colours, architectural proportions and detailing will be accepted as appropriate.

The strength of design guidelines varies from county to country, city to city and even neighbourhood to neighbourhood. The almost total lack of any guidelines in the economic “enterprise zones” of London’s Docklands encouraged overbuilding and lack of a coherent urban fabric. Clear design guidelines formulated for such North American cities such as Santa Fe, New Mexico, Santa Barbara, California,   Nantucket, Massachusetts, and Victoria, BC protect the special character of those towns.

Cities that try to develop design guidelines sometimes face bitter opposition from architects and builders who want to insist that the rights of the individual should supercede community interests. When Boulder, Colorado proposed in their design guidelines that certain materials such as corrugated aluminum and asbestos tiles were inappropriate façades in the historic sections of town, the news was featured in the New York Times.

Maintaining the Character of the City’s Architecture

In cities and towns with a well defined architectural identity the intrusiveness of an alien architectural form can seem overpowering…

Inappropriate structures are not always identifiable simply by their size. Sometimes the overall height may be appropriate, but the materials, or the size and proportions of windows and doors may be entirely hostile to the building’s context…

The Structure of a Healthy City

Similarities between the workings of a living organism and the functions of a city have been suggested by many urban analysts, and it is worth exploring this metaphor.

An understanding of the characteristics of a healthy living organism, and how that organism maintains its healthy state also provides a better understanding of the characteristics of a healthy city, and how the city can maintain itself in good health.

The role of the DNA in assuring correct form and direction of growth of the organism may also shed some light on the essential characteristics of a healthy and well-functioning city.

In a healthy body, cells are closely connected forming flesh, bones and blood, and enclosed in an envelope of skin that creates a distinct whole, identifiable as a human being. Every cell is cognizant of neighboring cells, and functions not as an independent unit but as a part of an integrated ensemble.

In a healthy city, too, the built fabric must be continuous. Individual buildings similar in height, form and appearance are connected to one another along streets and around urban spaces. The healthy city has an identifiable boundary; there are no wounds in the urban tissue, and no undifferentiated sprawling developments.

As the Nobel Prize winner Konrad Lorenz observes,

If you look at a cancer under a microscope, a cross section with cells of healthy tissue, it looks exactly like an aerial view of a city in which the old sections are surrounded by new, irregularly built regions or else by those that are monotonously geometrical - both are possible, after all. The parallels between the formation of malignant tumors and cities in a state of cultural decay are very wide ranging.”

For an organism to remain healthy, it must maintain the correct functional relationships between the various organs of the body (for example, the heart pumps blood through the body, which provides oxygen to the brain, which in turn sends messages to the muscles.) No single function can expand or close down unilaterally, since all are interdependent.

To remain healthy, a city too must maintain appropriate relationships between the different elements – dwellings, schools, shops, offices, etc. No single element can be underdeveloped at the expense of any other element without risk to the continued health of the city as a whole.

And no single population group such as working adults with cars can be given priority at the expense of other groups such as children without risk to the continued health of the city as a whole.

The vast areas of suburban sprawl that surround many cities in Europe as well as in North America unnaturally separate the city’s functions, make impromptu social contact and a sense of community impossible, and strangulate cities in automobile traffic as residents are forced to commute to work, school, shopping, or for social contact. For suburban tissue to be healed it is clear that suburbs need to receive high-density urban nuclei that provide all the necessary functions within walking distance.

As early as 1960, Lewis Mumford was calling for “tightening the loose and scattered pattern of the suburb, turning it from a purely residential dormitory into a balanced community . . . with a more varied population and with sufficient local industry and business to support it.” He also recommended that “ . . . the parts of the neighborhood should be joined together by green ribbons, pedestrian malls, and pleasances,” and stressed that “The one great requirement for open spaces in urban centers is to insulate them from the fumes, the noise, and the distracting movement of motor traffics.”

Side Effects of Incentive Development

The implant of a foreign organ, or the invasion of a hostile virus is met with resistance from the organism. The organism tries to reject what it identifies as alien to the system. In order to persuade the organism to accept a transplanted organ, immunosuppressive drugs are used to overcome the body’s resistance. However, one side effect of these drugs is to damage the immune system, and to render the organism incapable of resisting all infections.

In many cities, the community rises in local opposition to proposed large scale developments that would destroy the traditional fine textured, mixed use fabric. In order to ensure acceptance of a development, the community is offered financial incentives, and additional developments to reduce the negative impact of the proposed project.

However, as with immunosuppressive drugs, one side effect of these incentive developments may be to further destroy the community’s natural equilibriating systems.

The Shop/House: Building Block of a Healthy City

Victoria BCThroughout much of the world the primary building block, or “cell”, of the healthy city is the “shop/house” with shop, workshop or restaurant at street level, and residential dwellings above. The close proximity of living, working, socializing, of the public and private realms, are what makes the public realm so hospitable, and the private dwelling so convenient. This arrangement makes a city that is not only socially healthy, but also ecologically sound, eliminating unnecessary travel.

The street façade is the medium that makes possible a public life on the street, and connects the private world with the public world. Interactions between the private and public worlds are facilitated by a variety of openings - windows, bay windows, shutters that open fully or halfway, French windows, and balconies. It is essential that these apertures may be opened, so that interaction is possible between inside and outside. Window boxes, curtains, and blinds provide additional messages to the public realm about the persons living in surrounding buildings, thus making the street feel safer and more personal.

The street level deserves special handling, since it is here that the greatest degree of interactions takes place between those inside and those outside. The commercial shop fronts and their entrances need to be emphasized as different from the residential accommodation above.

Even if the building is large, the street level section of the façade should be broken into narrower shop frontages, and entrances should be accentuated. In this way the street façade presents an almost continuous succession of shop windows. The more carefully detailed the windows are, the more prestigious the merchandise often appears to be.

Every society has developed its own unique shop/house design, with its own variation in windows and door openings, materials and colours.

The Wisdom of the City

A healthy organism is one that is self regulating, where all the cells coordinate their function smoothly with all other cells, where there is a continuous flow of information back and forth, each cell “reporting” its condition, and receiving appropriate response from the other cells of the body.

Similarly, a healthy city is one in which finely tuned mechanisms exist for recognizing the needs of every individual, and group, and for responding appropriately to those needs. In other words, a city in which social interaction and a sense of community are very well developed, where individuals monitor the wellbeing of their neighbors and acquaintances, and where individuals take responsibility for each other.

The development of a sense of community in the city requires a constant flow of information. Information concerning the private world of individuals must become public knowledge, and events in the public realm must be reflected on in private. This process requires, also, a physical structure that supports information flow across the private/public barrier. This structure is found in the traditional shop/house described above.

The variety of activities at street level – shops, businesses, workshops, coffeehouses, theaters, and restaurant, generate social life and form the basis for social interaction. The private dwellings above provide for communication with the public realm through the building’s apertures – windows, balconies, doors, shutters and blinds. When residential use is withdrawn to high-rise buildings, or is oriented away from the street, it can no longer contribute to the essential dialogue between the private and public realms.

The communal wisdom needed to maintain a city’s special identity is dependent on continuous communication between all members of the community. There must be a frequent exchange of information, involving all, and keeping all members up-to-date on the current “health” and wellbeing of others in the community. And the behavior, actions and attitude of all must, in part, be visible and common knowledge. This implies an active and viable public realm, and appropriate and accessible urban spaces where the social life of the community can be enacted.

Who Can Save the City’s Identity?

We expect architects to understand what kind of building will be appropriate for a given location in a specific city. Even architects from other cities are assumed to be able to understand the city’s heritage, discover those characteristics that its citizens most deeply identify with, and create a building or a place that everyone finds delightfully appropriate.

We want to believe that architects can create buildings and urban spaces that enhance the urban spirit, that maximize the potential for diverse groups to live in harmony with one another, and that are conducive to a sense of urban wellbeing.

During the 20th century, our faith in the architectural profession was sorely tried. Those architects who follow the tenets of the “modern architecture” movement discipline themselves to ignore local traditions. The “Postmodernists”, the “Pop” architects, the “Brutalists”, the “Functionists”, the “High-Technology” architects and the “Deconstructionists” were all more concerned with the architectural fashions that are international in scope, and that are responses to a dialogue among the architectural profession, not responses to a specific cultural context.

To create an urban environment hospitable to the full range of the city’s inhabitants, and that facilitates their social interaction requires architects who comprehend the full range of social situations, cultural patterns, and personal agendas that need to be accommodated, who can empathize with a full range of humanity, and who enjoy the diversity of a fully functioning community social life.

Architectural education rarely recognizes these social, cultural, and psychological aspects of urban design, and architecture students are still selected (or self-selected) for their technical skills (mathematics, engineering or design) rather than for their understanding of other human beings.

Modern planning concepts of single function zoning and emphasis on automobile transportation have all but destroyed many North American cities and severely damaged the health of many European cities. Simplistic “modern” planning instruments must be abandoned in favour of a more sophisticated understanding of a city’s complex organization of functions.

Until architectural, urban design and planning education is transformed into the social arts that they should be, we cannot rely on these professions to create cities that maximize their civic potential. This wisdom resides in the dialogue between the diverse groups living in the city, and in the heritage of buildings and places that are well loved by the citizens. Community participation in planning and urban design is an essential element in maintaining a city’s healthy DNA.

Excerpted from: Suzanne H. Crowhurst Lennard and Henry L. Lennard, 1995. Livable Cities Observed. Carmel, CA: Gondolier Press. 7-23.
Not for quotation without permission.