II.

Human Development

Nicknamed Old Man River, the Mississippi emerged as a key transport and trade route when paddle-wheel steamboats became common in the late 1800s. Today river barges pushed by tugboats carry millions of tonnes of freight each year—mostly agricultural products, coal, steel, and petroleum. The principal cities on the river are Minneapolis, St Paul, La Crosse, Dubuque, Davenport, Keokuk, Quincy, Hannibal, St Louis, Memphis, Vicksburg, Baton Rouge, and New Orleans. At several cities the river is crossed by bridges.