 Duluth forms a metropolitan area with neighboring Superior, Wisconsin; together they are called the Twin Ports.The cities share the Duluth–Superior harbor and together are the Great Lakes' largest port, transporting coal, iron ore (taconite), and grain.A tourist destination for the Midwest, Duluth features the United States' only all-freshwater aquarium, the Great Lakes Aquarium; the Aerial Lift Bridge, which sits adjacent to Canal Park and spans the Duluth Ship Canal into the Duluth–Superior harbor; and Minnesota Point (known locally as Park Point), the world's longest freshwater baymouth bar, spanning .