In the literature many definitions of megacities and mega-regions are proposed (Urena et al., 2009; Pagliara et al., 2011). For example, Hall (2009) defines a mega city region as a "series of cities physically separated but functionally networked clustered around one or more larger central cities...

In the literature many definitions of megacities and mega-regions are proposed (Urena et al., 2009; Pagliara et al., 2011). For example, Hall (2009) defines a mega city region as a ?series of cities physically separated but functionally networked clustered around one or more larger central cities...