Slums and Housing Reform
The Journalist Who Walked Into the Dark and Changed How Cities Are Built
In 1890, a man named Jacob Riis took a camera into New York's most overcrowded tenements and produced photographs so disturbing that a future president read his book, threw it down, and immediately went to find him.
The Idea
The 19th-century city was, for most of its inhabitants, a place of staggering density and almost no regulation. In New York's Lower East Side, buildings known as 'dumbbell tenements' — named for their narrow air shaft, shaped like the weight — housed hundreds of people per acre, with whole families in single windowless rooms, sharing outdoor privies with dozens of neighbours. This was not unique to New York. London's East End, Paris's arrondissements before Haussmann, Bombay's chawls: the pattern was global. Industrialisation had pulled millions into cities faster than those cities could absorb them, and private landlords had every incentive to subdivide, overcrowd, and underinvest. What made the late 19th century a turning point was not the misery itself — that had existed for generations — but a shift in how it was seen. Social reformers began arguing, with increasing statistical rigour, that poverty was not merely a moral failing of individuals but a product of physical conditions. Bad housing caused disease, crime, and shortened lives. This was a genuinely radical reframing: it moved the unit of responsibility from the person to the environment. And once you accept that logic, the door opens to something previously unthinkable — that the state has not just the right but the obligation to intervene in how private property is built and occupied.
In the World
When Jacob Riis published 'How the Other Half Lives' in 1890, he was not the first person to document slum conditions — Charles Booth had been mapping London's poverty in meticulous detail since 1886 — but Riis had something Booth lacked: photographs taken with a flash, and a gift for narrative outrage. His images of children sleeping in stairwells and families crammed into coal cellars were not statistics. They were faces. Theodore Roosevelt, then a New York police commissioner, read the book in one sitting and showed up at Riis's office the next morning with a note reading 'I have read your book and I have come to help.' The two became close collaborators, and when Roosevelt eventually reached the White House, the political will to pursue housing reform at a national scale followed him there. But the more consequential result of Riis's work was local and architectural. New York's Tenement House Act of 1901 — directly shaped by the reform movement Riis helped ignite — mandated indoor toilets, windows in every room, and minimum courtyard dimensions. It was, in its moment, one of the most comprehensive pieces of housing legislation in the world. Within a generation, the dumbbell tenement was illegal. The question of what a city owed its poorest residents had been answered, at least in principle, with brick and mortar.
Why It Matters
The argument at the heart of 19th-century housing reform — that physical environments shape human outcomes, not just the other way around — is one that urban policy has been relitigating ever since. It underlies debates about social housing, about whether to demolish or renovate deprived estates, about why some neighbourhoods seem to trap people and others seem to launch them. There is something worth sitting with in how slowly this idea moved from obvious-in-hindsight to politically actionable. The suffering in New York's tenements was not hidden; it was simply not felt as a collective responsibility. What Riis and reformers like him did was change the frame — and once the frame changed, entirely different solutions became imaginable. That pattern repeats. Many of the most significant shifts in policy don't come from new data but from new ways of seeing existing data. The question of who gets to reframe a problem — and whose suffering becomes visible enough to demand a response — remains as live now as it was in 1890.
A Question to Ponder
What problem exists around you right now that is widely known but not yet widely felt as a collective responsibility — and what would it take to change that?
Get a new one of these every morning.
Start learning with Thinkable