Mega-cities and expanded outskirts. Expanding on the concept in Ciudad de Mexico

This article suggests a line of research about the growth and development of mega-cities, focused en their regional outskirts. Specifically, some elements seeking research on peri-urban areas on metropolitan expanded outskirts of the mega-cities are introduced, since it is in these zones where the biggest part of the metropolitan growth is taking piece. The most important interests of this article laid both on the metropolitan Ciudad de Mexico, about wich a urban pattern, more scattered than the ones in most part of the regional territory is shown, and on the springing up of many a great number of urban sub-centers, wich are reflected on a multinuclear structure, wich in turns becomes the basic structure of the metropolitan territories. At the same time, it is stated that the discussed theoretical and methodological aspects are also relevant for other big metropolitan areas, what may contribute to a more systematic analysis of the regional outskirt of the mega-cities, and in particular to its new territorial patterns.