This material investigates how modernist urbanism was applied in the creation of Brasília, considering its political and symbolic aspects, and how it influenced the configuration of public spaces. In addition to exploring their evolution based on an analysis that focuses specifically on the South Cultural Sector (SCS), a central area originally conceived by Lúcio Costa to be a cultural park integrated into the modernist urban fabric of the city. The SCS is an area that clearly reflects the ideals of modernist planning and also the issues that have arisen throughout history due to social, political, and functional transformations. The research examines the fundamental principles of modernist urbanism, architectural and symbolic intentions, their translation into the Brasília project and, in particular, into the guidelines of the Pilot Plan and the Southern Cultural Sector based on the heritage restrictions resulting from Brasília's designation as a UNESCO World Heritage Site.