Great Lakes Aquarium is one of few aquariums in the United States that focuses on freshwater exhibits (the Tennessee Aquarium is another example). It is housed in a three-story building in Duluth, Minnesota on the shores of Lake Superior and has numerous large and smaller satellite tanks that comprise the 120,000-US-gallon (450,000 l) facility. Construction took 3.5 years and cost around $34 million. All of the main exhibits of the 62,000-square-foot (5,800 m square) Great Lakes Aquarium (GLA) are based upon actual habitats in the Lake Superior basin. "Slices" of the St. Louis River, Baptism River, Pictured Rocks National Lakeshore, Kakagon Slough, Isle Royale and Otter Cove can all be viewed up close. The 85,000-US-gallon (320,000 l) Isle Royale is the main exhibit located in the very center of the building, and it extends to both the first and second floors allowing visitors to view it from many different angles. It contains fish like trout and lake sturgeon.