The Spanish modern urban planning system is still, after more than a century, clearly influenced by the historical conditions of its beginnings. It is generally acknowledged that the zoning experiences in Modesto, California, where the beginning of planning in the USA to protect housing values against nuisances; In the UK social reform movements related to the housing problems of a new urban industrial workers class with meager revenues and the menace of poverty led first to housing innovation and subsequently to garden cities. In France, the complex XIXth century in Paris, with the central role played by Haussman, finds no strong theoretical continuation until the later hygienist movement. The German urban planning develops many technical and theoretical tools in the context of a newly unified country at the end of thr XIXth century. All these national urban planning cultures share the hope to solve social and technical problems, but aesthetics also play a relevant role through such personalities as Sitte or Olmstead. In Spain the first half of the XIXth century is a national disaster, with the end of the Spanish American empire due to weakness resulting from Napoleonic wars and the lost years during the reign of Fernando VII. It becomes clear that city walls are no longer useful against modern weapons and are strong conditions contributing to miserable living standards in inner cities.

In 1858 and 1860 the Barcelona and Madrid demolition acts are approved. In Barcelona there is a conflict between state and city, as the first imposes Cerda’s project; this bears the name “ensanche” (widening), since then a generic name for city extensions. The regular grid is not a revolutionary layout, as it was a norm for newly founded American colonial cities of the Spanish empire; innovation was clearer for its theoretical framework, a comprehensive review of all the technical considerations associated to urban growth, clearly related formal issues and a social reform agenda less radical than in other examples but nevertheless new in approach. The public works minister, Pascual Madoz, introduced land management procedures that allowed demolishing the walls by an anticipated sale of future building rights. This contrasts with Paris, which retains its walls until 1919 due in part to the presence of open spaces inside, or Vienna, where the Ring also generates a new urban tissue but on a more reduced scale. Madrid and Barcelona get a planned growth instrument with larger territorial ambitions.