Discover The Wonders of Our Earth and the forces and life forms that shape our world with the Physical Geography Series. Most people know that water is unevenly distributed over the Earth's surface in oceans, rivers and lakes, but few realize how very uneven the distribution actually is. The World's oceans - 139 square miles of it - contain 317 million cubic miles of Saltwater. The atmosphere is another kink of ocean and moves water vapor around the world until it falls as precipitation. This program examines the Hydrologic Cycle and shows the major water movement in the United States. It also examines how ground water stores and releases water and looks at lakes, major river systems in the World and the World's estimated water supply.