In the middle of the 20th century, Lima grew rapidly due to migrations from rural areas to the unoccupied peripheries of the city. The new neighbourhoods, self-built and self-managed, quickly became the landscape of poverty, incorporating into their urban structure forms of traditional architecture that adapt to the context of the capital. On the other hand, the modern functionalist architecture acts on the consolidated city, destroying the traditional colonial architecture without respecting its scale or urban layout. Both cities come together from the seventies, converting Lima into a superposition of historical, urban and social layers and, drawing the attention of sociologists, architects and anthropologists who study how the unplanned growth of the city is spontaneously building the Peruvian identity. The article presents the critical point of view of one of the most important contemporary Peruvian architects, Juvenal Baracco, who proposes a methodology for the study of the developing city and translates it into a particular building, the School of the Air Force of Peru, located in the Peruvian capital. The study of Lima that makes in the workshop of the Ricardo Palma University, as well as his architectural proposals act on the idea of a growing city from which the final form is not yet know.