An esker is a long, winding ridge of sand and gravel that forms from the meltwater of glaciers. As glaciers retreat, they leave behind these unique landforms, which can stretch for miles. Eskers are often found in areas that were once covered by ice, and they provide important clues about the movement of glaciers during the last Ice Age. These natural formations are not only interesting to geologists but also serve as habitats for various plants and animals. The materials that make up an esker, such as sand and gravel, can be used in construction, making them valuable resources. Understanding eskers helps scientists learn more about past climates and the Earth's geological history.