Nations are linked inseparably to each other in many ways, including trade, finance, migration, climate, rivers, pollutant flows, communication, transportation, and treaties. These linkages must be taken into account when a nation is exploring alternative development strategies. Global models offer a new, important tool for the development of scenarios. WORLD3 was the first global model commissioned by the Club of Rome. The Futures Simulations model is a dynamic global model in which the nations of the world are represented as nine regions: United States, western Europe, other developed nations, countries belonging to the Organization of Petroleum Exporting Countries, Latin America, Africa, South Asia, China and other centrally planned developing countries. The GLOBUS model is an enormous advance in global modeling. GLOBUS is a computer simulation model of many important macropolitical and macroeconomic relationships within and among twenty-five prominent contemporary nations plus a rest-of-the-world entity. It is designed and used to explore possible solutions to long-term global problems.