Abstract : The analysis of historical centers of Cairo and Mexico City is divided into three areas with reciprocal influences: the analysis of urban landscapes, representations and heritage of urban policies. But for that heritage has Does it make sense? For whom and for what rehabilitate the old city of Cairo and the historic center of Mexico City? The comparative approach of two spaces, two landscapes belonging to opposing cultures, is then an advantage in distinguishing what is of particular local, specific to the societies studied and what belongs to the same external influence. The question is whether this external influence is powerful enough to overcome these local peculiarities or whether, conversely, every culture, far from yielding to a form of globalization of ideas, representations and practices of rehabilitation of historic centers, appropriates and reinterprets his way to the notion of heritage as well as "canons"of the rehabilitation of historic spaces. "Recipes" for a reconquest of the historic centers, and images of historic ideal that they generate, are they the same from one continent to another, regardless of urban forms, characteristics, traditions and cultures of each country and each city?