Yona Friedman has been destabilizing the architectural world since the 1950s. He is a pioneer of prospective architecture, renowned for his self-planning principles, mobile architecture and interest in local construction methods. Preferring the construction process , the "inhabitant" to the architecture and the structure, he is at the origin of the manifesto La ville spatiale which proposes an infrastructure that would be a spine for new spaces of sociability. Cells can be grafted, developed collectively and adaptable to the needs, uses and changes of the environment. These precepts still serve as a model for the invention of a "crisis architecture" many years later.