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
Geology of Minnesota the Minnesota and Mississippi Rivers. Eventually, the ice sheet melted, and the Red River gave Lake Agassiz a northern outlet toward Hudson Bay. As the lake drained away its bed became peatlands and a fertile plain. Similarly, Glacial Lake Duluth, in the basin of Lake Superior, was dammed by a glacier; it drained down the ancient course of the Midcontinental Rift to the St. Croix River and the Mississippi. When the glaciers receded, the lake was able to drain through the Great Lakes to the Saint Lawrence River. Giant animals roamed the area. Beavers were the size of bears, and