Contributor(s): Professor Kees Christiaanse | The idea of the open city as a place of social integration, cultural diversity and collective identity is perceived as an irreversible achievement of modernity, and fuels our visions for a sustainable urban future. Nevertheless, we are witnessing increasing fragmentation and seclusion, which threatens the existence of the open city. Suburban compounds, gated communities, university campuses, covered shopping malls, urban entertainment areas, airport security zones, holiday resorts, all tend to develop into privatized and controlled zones, which are connected with the city at large by a limited number of corridors and access points. Public space ' traditionally understood as the ultimate space of social encounter and equality - is being eroded by commerce, changing lifestyles and functionality. This lecture will address whether these conditions are destroying the sensible tissue of the open city, which are intended to encourage social interaction and balance. Are cities degenerating into secluded islands that denying a balanced urban totality? And how might the open city react to these developments?