Stephen Graham and Simon Marvin argue that we are witnessing a post-urban environment where decentralized, loosely connected neighborhoods and zones of activity assume the former organizing role played by urban spaces. Their theory of splintering urbanism involves the "fragmentation of the social and material fabric of cities" into "cellular clusters of globally connected high-service enclaves and network ghettos" driven by electronic networks that segregate as much as they connect. Dominique Lorrain argues that the process of splintering urbanism began towards the end of the 20th century with the emergence of the gigacity, a new form of a networked city characterised by three-dimensional size, network density and the blurring of city boundaries.[5]