United Nations is an organization.
United Nations . A replacement for the ineffective League of Nations , the organization was established on 24 October 1945 after World War II in order to prevent another such conflict . The organization 's membership grew significantly following widespread decolonization in the 1960s , and by the 1970s its budget for economic and social development programmes far outstripped its spending on peacekeeping . Some commentators believe the organization to be an important force for peace and human development , while others have called the organization ineffective , corrupt , or biased .