Duluth, Minnesota Lakes Waterway and the Saint Lawrence Seaway. Duluth forms a metropolitan area with neighboring Superior, Wisconsin, 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 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 . The city is also the starting point for vehicle trips along
Minnesota Point Light Bayfield of the British Navy, who chose a spot on Minnesota Point as the zero point of his mapping. The point is the eastern end of a great sand bar separating Superior Bay from the lake; the passage to the east of the point (known as Superior Entry) was the original outlet of the Saint Louis River. The Saint Louis River, which rises in Minnesota, becomes the Saint Louis Bay, then flows into Superior Bay and exits into Lake Superior via the ship canals, at each end of Minnesota Point (Park Point). Both Superior, Wisconsin, and Duluth, Minnesota, sprang up