Hostile architecture
Have you ever noticed seemingly innocuous design choices in public spaces—a strange bench, an unusual planter, or even a subtle slope—and wondered about their true purpose? This isn't always about aesthetics; sometimes, it's a deliberate strategy known as hostile architecture. These urban design elements are engineered to subtly, or sometimes not-so-subtly, guide human behavior and influence who uses public space, and how. Hostile architecture employs specific design elements in public spaces to deter certain behaviors, often targeting marginalized groups like the homeless or youth. While seemingly modern, this concept has historical roots in 'social engineering' through design, evolving from methods of segregation and protest control to today's more subtle forms. The ethical implications of hostile architecture are hotly debated, with critics highlighting its exclusionary nature and proponents emphasizing order and safety, sparking various forms of public resistance.
AI Summary
Have you ever noticed seemingly innocuous design choices in public spaces—a strange bench, an unusual planter, or even a subtle slope—and wondered about their true purpose? This isn't always about aesthetics; sometimes, it's a deliberate strategy known as hostile architecture. These urban design elements are engineered to subtly, or sometimes not-so-subtly, guide human behavior and influence who uses public space, and how.
- Hostile architecture employs specific design elements in public spaces to deter certain behaviors, often targeting marginalized groups like the homeless or youth.
- While seemingly modern, this concept has historical roots in 'social engineering' through design, evolving from methods of segregation and protest control to today's more subtle forms.
- The ethical implications of hostile architecture are hotly debated, with critics highlighting its exclusionary nature and proponents emphasizing order and safety, sparking various forms of public resistance.
The Unseen Hand of Design
Hostile architecture, also known as defensive design, is an urban planning strategy that uses elements of the built environment to purposefully influence behavior. It's not about structural integrity or safety; it’s about subtly, or overtly, shaping how people interact with public spaces—often without them even realizing it.
This design approach often targets individuals who tend to rely on or use public spaces more extensively. Think about youth, who might gather in parks, or people experiencing homelessness, who might seek shelter. The underlying goal is to restrict certain physical behaviors, making some actions uncomfortable or even impossible.
Common Manifestations
Perhaps the most well-known example is the 'anti-homeless spike'—small, pointed studs embedded in flat surfaces. These aren't decorative; they're there to make sleeping or even sitting on a ledge utterly impractical. But hostile architecture extends far beyond just spikes.
Other common manifestations include sloped window sills designed to prevent sitting, or public benches with strategically placed armrests that make lying down impossible. Even seemingly mundane features like water sprinklers that activate intermittently or trash bins with small openings can be forms of this subtle control, deterring everything from littering to skateboarding, public urination, or loitering.
A History of Social Engineering
While the term 'hostile architecture' is relatively new, the underlying idea of using civil engineering for social engineering is not. We can trace its antecedents back to the 19th century, with things like urine deflectors on buildings or urban planning choices aimed at segregation, like Detroit's Eight Mile Wall.
A striking example comes from American urban planner Robert Moses. In the 1930s, he designed a stretch of Long Island's Southern State Parkway with deliberately low stone bridges. The hidden agenda? To prevent buses, heavily relied upon by lower-income residents and African Americans, from accessing certain beaches, which were then reserved for wealthier car owners.
Across the Atlantic, 19th-century Paris saw its narrow, winding streets dramatically widened under Baron Haussmann's renovation. While often cited for aesthetic and hygienic reasons, a secondary, unstated purpose was to make it harder for revolutionaries to erect barricades and for the military to quell protests.
Modern Roots: Crime Prevention Through Design
The modern form of hostile architecture largely emerged from the design philosophy known as Crime Prevention Through Environmental Design, or CPTED. This approach aims to reduce crime and protect property by manipulating the physical environment itself.
CPTED focuses on principles like natural surveillance, ensuring clear sightlines; natural access control, guiding movement; and territorial enforcement, creating a sense of ownership. The theory is that by designing spaces with these ideas in mind, potential offenders will be dissuaded from committing crimes.
Beyond Crime: Economic and Social Agendas
However, the motivations behind hostile architecture often extend beyond just crime prevention. In many modern capitalist cities, there's a strong incentive to eliminate visible signs of homelessness from communal spaces. The concern is that such visibility might deter investment from wealthier individuals or businesses.
In places like England, much of this architecture has been linked to governmental desires to combat what's perceived as an 'anti-social street scene'—behaviors like begging or public drinking. The design, in essence, becomes a tool for social clean-up, aiming for an appearance of order.
Design Apartheid
Architect Rob Imrie coined the term 'Design Apartheid' to describe how built forms can implicitly assume a population's 'sameness' and 'able-bodiedness.' This can inscribe exclusionary values directly into our shared spaces. Consider Le Corbusier's Modulor, an anthropometric aid for architects.
The Modulor, based on the proportions of a 'six-foot tall, muscular, powerful' upright male, implicitly excludes anyone who doesn't fit this ideal—people with disabilities, different body types, or even just those who prefer to recline. Such design choices, however subtle, define who belongs and who doesn't.
The Many Faces of Hostility
Deterring Resting and Camping
Perhaps the most widespread applications are those designed to prevent sleeping or prolonged stays. Many cities, including Tokyo and London, feature benches with steeply sloped seats, forcing users to constantly support themselves with their feet, making comfortable rest impossible. Others feature multiple armrests positioned down the center, dividing the seating surface into individual segments too small for someone to lie across.
Beyond benches, cities deploy other physical obstacles. Seattle, for instance, installed dense bicycle racks to prevent homeless individuals from setting up tents. In Oregon and San Diego, large boulders and jagged rocks have been strategically placed along freeways and underpasses to deter transient encampments.
Physical Barriers and Removal
Fences and grates are another common exclusionary design. They're often installed in sheltered spots—under stairs, bridges, or near building fan systems that emit warm air—precisely where someone might seek refuge from the elements, creating physical barriers to essential shelter.
Sometimes, hostile architecture isn't about adding features, but about taking them away entirely. The removal of public benches, for example, is a common tactic. As author Fredrik Edin points out, benches are removed precisely because the public uses them, with a New York City Subway tweet once starkly admitting benches were removed 'to prevent the homeless from sleeping on them.'
Sensory and Surveillance Deterrents
Sensory deterrents take a different approach. In Sweden, loudspeakers play music to deter addicts. The UK and Germany have deployed 'anti-loitering devices,' like 'The Mosquito,' that emit a high-frequency monotone sound, audible mostly to younger people, making spaces uncomfortable for them. These aim to make specific public areas less desirable for certain groups.
Sprinkler systems can also be weaponized, often employed in areas where permanent spikes are deemed too aggressive. This solution involves spraying water intermittently on those who occupy a particular place at a specific time, effectively denying shelter. Furthermore, security cameras, while not physically restrictive, create a fear of retaliation for 'socially taboo' actions, becoming a potent form of remote oversight.
Aesthetic Deterrents
Even seemingly aesthetic elements like large flower pots, art installations, or planter beds can be deployed as hostile architecture. These items are strategically placed to prevent sleeping or camping in certain areas, often on pavements where homeless people might otherwise seek rest.
The Great Debate and Resistance
Hostile architecture generates significant debate. Proponents argue that it establishes a clear sense of ownership, maintains order and safety, and deters crime. Critics, however, contend that it makes public spaces hostile for everyone, disproportionately targeting vulnerable populations, pushing them further to the margins and fostering feelings of displacement and insignificance.
Public outrage has, at times, led to the removal of particularly egregious examples, such as anti-homeless spikes in London. Beyond protests, tactical urbanism includes actions like 'chair bombing,' where seating is installed where it's absent, or vandalism of anti-homeless spikes and armrests to undermine their intended effects.
Identifying hostile architecture isn't always straightforward. Some designs, like spaced-out singular chairs, might be interpreted as exclusionary or simply cultural preference. Researchers suggest evaluating these designs within the wider social and political context, recognizing motivations like anti-homelessness legislation.
Despite the widespread implementation of these designs, it's important to note that as of March 2020, no wide-scale empirical study had been conducted to measure the full impact of hostile architecture on the well-being of homeless people or other targeted populations.
Article
Hostile architecture
Bolts installed on the front steps of a building in Marseille, France to discourage sitting and sleeping
Hostile architecture, is an urban design strategy that uses elements of the built environment to purposefully guide behavior and exclude the public from public space access. Hostile architecture is "hostile" because it covertly (and sometimes overtly) keeps people away. Hostile architecture stems from urban planning decisions that aim to fight perceived social disorder and often targets people who use or rely on public space more than others, such as youth, poor people, and homeless people, by restricting the physical behaviours they can engage in.
The term hostile architecture is often associated with items like "anti-homeless spikes" – studs embedded in flat surfaces to make sleeping on them uncomfortable and impractical. This form of architecture is most commonly found in densely populated and urban areas. Other measures include sloped window sills to stop people sitting or resting, bumps on buildings, planters and boulders on sidewalks to deter tents, benches with armrests positioned to stop people lying on them, water sprinklers that spray intermittently, and public trash bins with inconveniently small mouths to prevent the insertion of bulky wastes. Hostile architecture is also employed to deter skateboarding, BMXing, inline skating, littering, loitering, public urination, and trespassing, and as a form of pest control.
Background
Hostile architecture
Although the term hostile architecture is recent, the use of civil engineering to achieve social engineering is not: antecedents include 19th-century urine deflectors and urban planning in the United States designed for segregation. One example of this was the Detroit Eight Mile wall, built in 1941, and meant to segregate white neighborhoods from black neighborhoods. American urban planner Robert Moses designed a stretch of Long Island Southern State Parkway with low stone bridges so that buses could not pass under them. This made it more difficult for people who relied on public transportation, mainly African Americans, to visit the beach that wealthier car owners could. Outside of the United States, public space design change for the purpose of social control also has historic precedent: the narrow streets of 19th century Paris, France were said to be widened to help the military quash protests.
Its modern form is derived from the design philosophy crime prevention through environmental design (CPTED), which aims to prevent crime or protect property through three strategies: natural surveillance, natural access control, and territorial enforcement. According to experts, exclusionary design is becoming increasingly common, not least in large cities such as Stockholm.
Consistent with the widespread implementation of defensible space guidelines in the 1970s, most CPTED implementations as of 2004 were based solely on the theory that proper design and effective use of the built environment could reduce crime, reduce fear of crime, and improve quality of life. Built environment implementations of CPTED seek to deter crime by manipulating the environment in which crimes occur. The six main concepts according to Moffat are territoriality, surveillance, access control, image/maintenance, activity support, and target hardening. Applying all of these strategies is key to preventing crime in any neighborhood, crime-ridden or not.
Beyond CPTED, scholarly research has also found that modern capitalist cities have a vested interest in eliminating signs of homelessness from their communal spaces, fearing that it might discourage investment from wealthier individuals. In England, much of their hostile architecture has been attributed to a desire by the government to combat an anti-social street scene, taking the form of begging and street drinking.
Design Apartheid
Design Apartheid, a term coined by architect Rob Imrie, is the assumption of sameness and able-bodiedness in a population when designing built forms. The built forms are inscribed with the ableist values of the society. An example of design apartheid can be seen in Le Corbusier's diagram of the Modulor, which utilises proportions of the body as an anthropometric aid to help architects design buildings by presenting an image of an upright male who is six feet tall, muscular, powerful, and showing no evidence of either physical or mental disability.
Applications
Spikes
Anti-homeless spikes in New York, designed to prevent sitting.
Hostile architecture can take the form of spikes, bumps, or other pointed structures. They are typically placed on ledges outside buildings, under roofs or other places where people seek rest or shelter, and also around shops. The property management company Jernhusen uses a variant by placing pipes instead of spikes in several places at Stockholm Central Station. In 2014, images circulated on the internet of a place in London where homeless people used to sleep. The ground had been fitted with sharp, upward-pointing spikes to deter people who used to sleep there, but after widespread protests, the anti-homeless spikes were removed. Former UK Prime Minister Boris Johnson has called the spikes "stupid". There are also anti-homeless spikes which are intended to ensure that people do not, for example, sit against a house wall or stand in a particular place. It is difficult to assess how many different types exist adequately, but it is certain that there are many forms of the phenomenon, including split bricks which form cracks, various forms of bent metal pipes, and plates welded upwards to form spikes.
Sleeping deterrents
The "Camden bench", used in London, has a design that is stated to discourage sleeping, littering, skateboarding, drug dealing, graffiti and theft
Simme seating prevents users from lying down
In many large cities, for example Tokyo and London, benches have been designed to prevent people from sleeping on them. These benches have been constructed so that the seat slopes at an angle, requiring the user to support themselves entirely with their feet; such benches are ubiquitous at bus stops across the United Kingdom. Another deterrent design is to include armrests placed down the center of the bench, preventing the user from lying down across the seats.
Camden Borough Council in London commissioned concrete-block benches (dubbed "Camden benches") designed to discourage uses such as sleeping, skateboarding, and placing stickers. There are other variants, in which level differences are absent but they tend to be either too short to lie on, or have iron pipes placed two-thirds of the way in, or multiple armrests placed along the entire length of the bench. Such benches are common in airports.
Other types of seats, such as Simme seats, are designed to be too small to accommodate lying down or sleeping. They are installed in locations where homeless camping is prevalent.
When the City Tunnel in Malmö, Sweden, was opened in 2010, the design of the benches on the new train platforms was reported to the Equality Ombudsman because the benches were tilted so much that they were difficult to impossible to use for sitting. The Swedish state-owned real estate company Jernhusen has also used so-called "homeless-proof" benches at the train station in Luleå, with seven iron bars at 47 cm (19 in) intervals per bench. Jernhusen's press officer maintained that they "put in the armrests primarily to make it easier for the elderly and disabled to sit and stand up" but admitted in an interview that the perceived orderliness problems at the station building influenced how the benches were designed. Another example of a company that has installed such benches is Berliner Verkehrsbetriebe, Berlin's local public transport company.
Some examples of sleeping deterrents involve temporary changes to buildings. An example of this occurred in a Liverpool building, previously the Bank of England headquarters, in December 2016. A blue, sloping steel structure covered in oil was placed over the stairs at night, so that the homeless who used to sleep and rest there would not stay.
Camping deterrents
In Seattle, Washington, United States, the city government installed bicycle racks to prevent homeless people from camping.
Since 2013, the Oregon Department of Transportation in Oregon, United States, has deployed large boulders at eight locations that had been the sites of transient camps in Portland. These boulders were installed to deter illegal camping near the freeways.
San Diego raced to install jagged rocks underneath freeway overpasses before a Major League Baseball game.
Fences or grates
Fences or grates are a common form of exclusionary design, often used to prevent access to places where there is protection from the elements, for example under stairs, bridges, or near fan systems that blow out hot air.
In the spring of 2015, the City of Stockholm, Sweden, erected a 200,000 kr (~22,900 USD) fence to prevent homeless people from seeking shelter under a staircase in Kungsholmen.
Removal
Passengers sit on the floor waiting for trains in the Moynihan Train Hall in New York City due to a lack of benches, which some critics have argued is designed to keep away the homeless.
Sometimes exclusionary design is not about adding features, but rather about taking them away. Fredrik Edin, who has written a book on exclusionary design, says that removal is the most common form of exclusionary design, in which, for example, benches used by the public are removed precisely because the public uses them. One example is when representatives of the New York City Subway announced via social media in 2021 that "benches were removed from stations to prevent the homeless from sleeping on them." The agency later said the tweet was a mistake. Benches at certain locations at Stockholm Central Station were removed in 2015 in favour of chairs, and benches were also removed at Luleå railway station. Their press officer stated that they had problems with the station being used as a warming shelter. Many public toilets have begun to be removed in the UK in places considered to be untidy.
Security cameras
One of the most common forms of hostile architecture is surveillance. While security cameras do not physically prevent people from engaging in certain behaviors, they can restrict such behaviors in public spaces by enabling remote oversight and increasing the fear of retaliation for socially taboo actions. In cities like Cincinnati, there has been a noted sharp increase in the number of CCTV cameras in public spaces since the 1990s.
Art, planter beds and flower pots
A large, sturdy flowerpot outside a building in Stockholm, designed to discourage use of the space, without looking aggressive
This type of exclusionary design may involve, for example, installing a large flowerpot where homeless people previously slept on the pavement. Other examples that have occurred include a stone painted in rainbow colours, removing blocking shrubbery from a sidewalk, and "fun"-shaped seating.
In 2023, businesses, homeowners and the public works department in San Francisco began using steel tubs as garden beds to deter camping and sleeping rough. Some residents have objected that to the deployment of planters, citing a continued lack of funding for overcrowded shelters; to the haphazard placement of planters; and removal of sidewalk space. Residents with mobility issues raised concerned about reducing the accessibility of sidewalks. The city instituted a free permitting system for street planters in response.
Loudspeakers
In Sweden, loudspeakers in Finspång have played music to get people with a substance use disorder to leave certain places. In the USA, UK and Germany, so-called anti-loitering devices (e.g., The Mosquito) have been installed to prevent young or homeless people from lingering in areas where they are installed. The devices work by emitting a monotone sound at such a high frequency that most people after adolescence lose the ability to hear it. Critics have stated that the devices constitute a violation of human rights and also comment that the phenomenon would create a "dangerous gap" between young people exposed to it and older people who can avoid it. In Germany, classical music has been used in an attempt to keep drug users away. In Berlin, a plan to use atonal music at S-Bahn stations was withdrawn after criticism.
Sprinklers
Sprinklers are used in areas where spikes are considered too permanent; this solution involves spraying water on those who are in a particular place at a particular time.
In the Skid Row neighborhood of Los Angeles, sprinklers were turned on at night to deter encampments in parks.
The Strand Bookstore in New York used such a system in 2013 to deter homeless people from sleeping outside the store at night. Bonhams in San Francisco was criticised for an external sprinkler system that it claimed was used to clean "building and perimeter sidewalks during non-business hours intermittently over a 48-hour period", and which was also a point where homeless people gathered.
Sex in robotaxis
"Love in Traffic", an academic and industry workshop, was held in Sweden in September 2026. Subtitled "Physical and Digital Design Against Consensual Sexual Activity Inside Public and Shared Automated Vehicles", it studied methods of dissuading "content creators" from filming themselves having sex in robotaxis.
Reception
Hostile architecture
Opposition to hostile architecture in urban design states that such architecture makes public spaces hostile to all people and especially targets the transient and homeless populations. Proponents say that clearly establishing a sense of ownership over the space helps maintain order and safety and deter crime and unwanted behaviors.
Examples of hostile architecture circulating within UK media have led to negative reception. Nonetheless, types of hostile architecture have increased. For example, Selfridges in Manchester installed metal spikes outside their store for the purpose of reducing "litter and smoking," which suggests hostile architecture may be implicated for one reason but explained by another.
Often as part of a larger pattern of tactical urbanism, some opponents of hostile architecture have responded to it directly to undermine its intended effects. Where public seating is absent or inadequate, some have built and installed seating themselves in an act called "chair bombing". Others have removed or vandalized anti-homeless spikes and armrests in protest of anti-homelessness legislation. Some members of England's homeless community interviewed by researchers have noted that hostile design contributes to their displacement and feelings of insignificance, as it appears that local business interests are prioritized over their survival.
Identification
Some forms of hostile architecture are easy to identify, while others could be interpreted as either exclusionary or non-exclusionary, such as spaced-out singular chairs constructed at a playground in Sweden, which may appear intentionally designed to dissuade homeless sleeping, or as an acknowledgement that Swedes consider it impolite to sit near strangers. Some researchers have said that hostile architecture should be evaluated within the wider context of the community, and should recognize the social and political forces motivating a particular design choice, such as anti-homelessness legislation or sentiments.
Evidence
Hostile architecture
As of March 2020, no wide-scale empirical study has been conducted to measure the impact of hostile architecture on the wellbeing of homeless people or other targeted populations.
Gallery
Hostile architecture
• Spikes added around fountain in Government Center, Miami, in 2011 at downtown transit center • Ledge with skatestoppers preventing skateboarders from grinding • Spikes on a ledge in Boston to prevent sleeping or sitting • Spiked handrail, presumably preventing users from sliding down • Floor spikes in Shoreditch, London, U.K, designed to prevent people from sleeping on the ground. • Benches with metal pipes (not armrest) to prevent lying down at a train station in Vienna • Pins prevent pedestrians from resting on ledge • Anti-homeless object in Shinjuku Station underpass • Strips of metal balls affixed to what was previously a bench in front of the Dublin's Last Supper mural in Dublin, Ireland