A lake is a body of water completely surrounded by land. Lakes can either by salty or fresh water. Most lakes are in places where glaciers used to exist. When a glacier moves forward, it carves away a deep valley and when the ice melt s it forms a lake in the valley. Other lakes are formed in craters or when a river changes its course.
This is a satellite image of the five Great Lakes in North America. It is the largest group of freshwater lakes in the world. The largest and deepest one is Lake Superior located at the top left. Lake Baikal in Siberia, Russia is the deepest lake in th e world.
Image Courtesy Environmental Research Institute of Michigan,Ann Arbor. For additional information see http://www.erim.org © ERIM
source: windows to the universe