This chapter examines the historical evolution of utopian and dystopian theories from the Renaissance to the twenty-first century, focusing on how these concepts are inscribed in urban environments—especially under conditions of global crisis such as pandemics. It considers the influence of thinkers including Thomas More and Michel Foucault, with particular emphasis on Foucault’s notion of heterotopias as a lens for analyzing the city not merely as a physical space but as a site of tension, resistance, surveillance, and alternative possibilities. Building on this, theorists such as Lefebvre, Soja, and Cenzatti reframe heterotopia as dynamic, often ephemeral, social practices of difference. Urban planning and architecture are thus read against the tension between idealized utopian visions and dystopian realities marked by exclusion, oversight, and inequality. Crises, in turn, reconfigure urban life, revealing both structural vulnerabilities and new forms of collective imagination. Ultimately, the city appears as a key arena for negotiating utopian hopes and dystopian anxieties.