The paper highlights how the mega events have social and symbolic impacts as well as economic and urban. Indeed, mega events have re-shaped either the imagine of a city and the physical structure and the social organization of space. The remaining traces of certain mega events have become part of the history of the city, turning into the urban legacy. The paper will not draw the history of International Expositions and Olympic Games, on the contrary it will present, throughout some case studies, those elements that have facilitated their transformation and might explain the philosophy behind. Turning an exceptional event into the routine of city government it is a rather difficult task. In specific, the contribution will highlight the importance of the link between project and planning, the need of a consensus for fostering energies and capital resources, the pressing issue of the risk of disillusion, and last but not least the risk of reinforcing the territorial inequalities. Certainly, mega events produce structural transformation of the city and therefore the social and territorial dynamic might change. The urban regeneration policies that aim to improve urban competitiveness, frequently targeted areas that in the global scene are profitable in economic and symbolic terms. Inevitably, the marginalised areas are still in the shadow and social exclusion and urban segregation are perpetuated.
Keywords: Legacy, mega events, city, urban transformation, urban project, territorial inequalities