The United Nations System consists of the United Nations, its subsidiary organs (including the separately-administered funds and programmes), the specialized agencies, and affiliated organizations. The executive heads of some of the United Nations System organizations and the World Trade Organization, which is not formally part of the United Nations System, have seats on the United Nations System Chief Executives' Board for Coordination (CEB). This body, chaired by the Secretary-General of the United Nations, meets twice a year to co-ordinate the work of the organizations of the United Nations System.