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
North Shore (Lake Superior) at Silver Bay, and it quickly became the major taconite shipping port. Minnesota taconite produces over half of the iron mined in Minnesota at the present date. Northern Minnesota is essentially covered with one large forest. Although the potential for a lumber industry was recognized early in the course of European settlement, the distances that it would have to be shipped made it uneconomical. But as eastern forests were logged out, the lumber industry moved into Wisconsin and Minnesota.. Lumber and forest products were shipped by rail from Duluth and Superior, Wisconsin to southern and eastern mills. Because of conservation