The World Zone Authority was the successor to the United Nations on Earth in the early 21st century. Nations were grouped into Zones answerable to a World President, headquartered in the UN's old New York building. Each Zone had its own Controller but a centralised security agency under a World Security Chief had jurisdiction over the whole body, and visas and passes were needed to move from Zone to Zone. Rockets had replaced planes: the Australia-Hungary flight took two hours. (TV: The Enemy of the World)