In 2015 Milano hosted for 6 months the World's Fair, focused on the issues of sustainability and nutrition. When Expo closed its gates the arisen question has been what to do with the 100 ha exhibition site in the North-West periphery. The theme is particularly thrilling for two reasons: irst, the re-use of structures for mega-events has a long past but still few solutions; second, Milano, as a post-industrial city, has a history in coping with abandoned areas, and now more then ever is ready to make use of an innovative spatial design. Goal of this master's thesis is to turn the Post Expo issue into an occasion of further development, to transform the former fairground into a space for trialling ideas and for researching solutions to the emerging problems of the city. I have decided to work with scenarios, since in the irst phase of planning of big sites they represent a suitable tool for the evaluation of the proposals. The 3 possible Expo futures are based on 3 density models (low, middle and high) which can be found in the Milanese landscape. In each scenario are developed distinctive urban functions (agricultural park, social housing, creative city) as well as the consequences that these mean for the whole metropolitan system. The 3 designs are not a diktat, but possible answers, among many, to the Post Expo issue: there is not an absolute best and worst solution, but there are better solutions in relation to speciic criteria, like recycling of the structures, proitability, urban urgencies... . Constant feature of the 3 scenarios is the role of new centrality that Expo plays in the metropolitan context.