The first ingredient of a nation's economic system is its natural resources. The United States is rich in mineral resources and fertile farm soil, and it is blessed with a moderate climate. It also has extensive coastlines on both the Atlantic and Pacific Oceans, as well as on the Gulf of Mexico. Rivers flow from far within the continent, and the Great Lakes -- five large, inland lakes along the U.S. border with Canada -- provide additional shipping access. These extensive waterways have helped shape the country's economic growth over the years and helped bind America's 50 individual states together in a single economic unit.