Its primary objectives are the maintenance of international peace and security. Since 1976, the United Nations has been concerned with the development of human settlements and the phenomenon of urbanization. Every 20 years it organizes a major international conference (HABITAT I in Vancouver in Canada in 1976, HABITAT II in Istanbul in Turkey in 1996, HABITAT III in Quito in Ecuador in 2016). Its specialized agencies are UN-HABITAT, UNDP (United Nations Development Program), etc.