In the 1920s, the modern city seemed to hold nothing but promise: order, cleanliness, rapid movement, economic growth and technological progress. But disaffection grew as neatly planned metropolises sprawled and outpaced themselves. In the 1950s, urban planners recommended more order, urban renewal and slum clearances. Dutch artist Constant Nieuwenhuys offered a different alternative in the 1960s: a city of linked megastructures called New Babylon that would drift high over the regimented city and provide a place without order—a place “for playing, for adventure, for mobility.”

Since then, plenty of urban planners have taken up the quest to improve our cities. Among the most intriguing strategies is the linear city, an orderly slice of metropolitan energy dominated by a single path of movement. This vaguely recalls agricultural long-lot settlements in which houses and barns, fronting long narrow fields, squeeze together along a single roadway. In linear settlements, neighbors can’t help but interact with each other as they go about their lives. They also can’t avoid each other. Every interaction becomes more a product of the community’s planning than of its people’s desires. 

The Swiss architect Le Corbusier greatly amplified this linear arrangement in his 1930s design for Algiers. He sought at once to tidy the sprawling city and to command its complex terrain. The Obus (“Shrapnel”) Plan would have disrupted everything about the old city. Its most dominant feature was a sinuous highway lifted over the hills on a long wall of housing—residences for 180,000 people overlooking the Mediterranean. Although never built, the urban housing scheme in Algeria anticipated Le Corbusier’s influential Unité d’Habitation (Housing Unit), which his firm built on several sites in Europe. It was a long concrete block with hundreds of two-story apartments open to outdoor views but also facing broad interior streets, where people would enjoy chance meetings with their neighbors—an entire city caught up in one building.

The British New Brutalist architects Alison and Peter Smithson expanded this idea of “streets-in-the-air” for public housing projects in London. Their unbuilt Golden Lane design proposed a meandering slab to house 500 people. It promised, they proclaimed, “an infinitely richer and more satisfactory way of living in cities” because people could encounter each other on elevated thoroughfares without ever descending to the surface below. All these plans failed to consider that not all chance meetings are benign, and that mutual confinement does not constitute a community. A built version of the Smithsons’ interior streets at Robin Hood Gardens public housing was disastrous, inviting vandalism and crime hidden away from the observant eyes of the city. That building was demolished in 2017.

Hopefully, this will not be the fate of the most audacious linear city project ever attempted: The Line, now under construction in Saudi Arabia. It will be a 105-mile-long conurbation of nine million people, framed by two immense mirrored walls—1,600 feet high and spaced 650 feet apart.¹ The planned reflective shard stretching across mountains and deserts assures “a revolution in civilization” in which “residents will have access to all their daily needs within five-minute walk neighborhoods.” That seems a narrow promise. A hundred years of modern sculptural city design suggests that this new linear city may offer little more than geographical constraint, rather than a richly spontaneous, satisfyingly dynamic urban way of life.