As the geographer and urbanist Edward Soja wrote in 2000, “Something extraordinary happened to cities in the late 20th century.” This is one of the simpler statements ever penned by the usually verbose theorist, yet it still says a mouthful. The city of today—especially the “Western” city, the city of the global north, the city of advanced capitalism, the American city—is unique in history for its diversity, its size, its complexity, its interconnectivity, its unevenness, and its unwieldiness. But in other ways, the city appears to be turning toward (or rediscovering) a way of making and remaking itself that is on some counts rather instinctive, quaint, and even traditional. People are doing it themselves, informally and spontaneously—whether as needed or simply as inspiration strikes. People are installing fanciful and functional infrastructure which is intended to improve everyday life, firms are developing projects in underutilized spaces to make contributions even when there is no client, and community groups are taking neighborhood planning into their own hands.

From what social and spatial context does the current trend toward an informal, spontaneous, and do-it-yourself (DIY) urbanism emerge? And what, in turn, does this trend say about the American city?

The concept of informal design is fairly recent, and imperfect at that. We are creatures who transform our surroundings, and the formality with which we build our environment is relative. As recently as a couple of centuries ago, the Western city was still largely the popular bricolage it had always been. It featured a considerable amount of top-down design, as even ancient cities had, but was constructed day-in and day-out by its inhabitants as a specific need arose, right down to a good deal of the architecture and streetscaping. It was largely during the 18th and 19th centuries that the shaping of the urban built environment became increasingly formalized and professionalized, in keeping with the wider standardization that came with the enlightenment, modernity, and industrialization. From the planning efforts of John Nash, Baron Haussmann, and Frederick Law Olmsted in the 19th century, to the widespread adoption of building and zoning codes, to the introduction of Le Corbusier’s modernism, and then to the development of broken windows theory, by the 20th century Western cities were not only master-planned but tightly controlled and regulated, right down to the streets and sidewalks—to be altered only by professionals.

There were exceptions: Graffiti persisted, as did the operation of informal commercial spaces and the construction of illegal shelter. So too did small-scale, local beautification efforts, and the time-honored (now often legally required) practice of clearing the public sidewalk in front of your home or business. But on the whole, we stopped thinking of the urban environment as open to popular reinterpretation. It is now remarkable to most people that someone might apply their design skills to create a functional infrastructural improvement outside of the formal process, such as painting a bike lane where the city hasn’t bothered, converting a derelict phone booth into a book exchange, fostering community and engagement through a whimsical public installation, or building a project whose only client is the common good.