Hostile architecture is an urban design trend in which public spaces are constructed or altered to discourage people from using them in a way not intended by the owner. Also known as defensive architecture, hostile design, unpleasant design, or defensive urban design, it is most typically associated with aggression against the homeless in the form of "anti-homeless spikes" — studs embedded in flat surfaces to make sleeping rough uncomfortable and impractical.

 

Hostile architecture often targets the city's most vulnerable, both intentionally through anti-loitering and anti-skateboarding measures and unintentionally by making the cityscape hostile to all parts of the public, especially seniors, people with disabilities, and children.

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It could easily be suggested that the use of hostile architecture could be a way of segregating the social classes, and expanding the gulf between the poorest and richest in society.