From Lake Itasca, Minnesota, to Cairo, Illinois, the upper Mississippi River flows through America's heartland for over 1100 miles. Its currents have borne the Indian's canoe, the explorer's dugout, and the trader's packet. Jacques Marquette, Louis Jolliet, and Zebulon Pike tested its strength. Mark Twain gave it life in literature. Paddle-wheelers by the hundreds ferried lesser-known passengers over its waters during the halcyon days of steamboating in the 19th century. Into the Great River pour the St. Croix, Chippewa, Black, Wisconsin, Rock, Illinois, Missouri, and Ohio. Along its banks have flourished St. Paul, Winona, La Crosse, Davenport, Keokuk, Quincy, and St. Louis. For a time diminished in importance by the railroads, the Great River came back into its own in the 20th century through dredging and damming. The present nine-foot channel and a series of locks and dams allow 300-foot barges to transport coal, cement, grain, and other products vital to the region's economic well-being. Imposing in size and beauty, violent and muddy in flood-stage, calm and serene on a summer morn, the Great River sustains life and livelihood within itself, along its banks, and upward in the hinterlands east and west.