This chapter discusses the informal and illegal behaviours considered as licit in their relationships with the urban space. It addresses the issue by discussing some examples from Rome in order to demonstrate how these behaviours, which can have different origins, justifications and orientations, might be functional within certain systems, instead of being subversive of given institutional assets and current market logics. The chapter explores the shift from illegality into licitness, while considering its causes, meanings and implications. In the Italian administrative culture, illegal and illicit behaviour is a well-known – and researched – phenomenon. The chapter examines the idea of different geographies of illegality, illicitness and informality and, more precisely, and argues that the North/South divide, as expressed in the literature, is not helpful. In bare quantitative terms, more than 50 per cent of the existing buildings in Rome are somehow, although with different degrees of illegality.