The Great Lakes, known as America's Inland Seas since they are so large, are made up of Lakes Huron, Ontario, Michigan, Erie, and Superior (HOMES). The lakes together border 8 states and contain 23 quadrillion liters of water. The lakes provide a variety of habitats that is home to over 3,500 species.
The lakes create a water flow that keeps water clean and circulating through all of the lakes and out to the Atlantic Ocean, after flowing over Niagara Falls. The interconnected lakes house about 20% of the world's supply of fresh water. The consistent flow of the lakes provides natural water filtration, flood control and nutrient cycling. The lakes also provide drinking water for over 40 million people. Given all the benefits the lakes provide to the surrounding areas, organizations have worked to protect the water from pollutants and invasive species.