Introduction to the Mississippi River: The Mississippi River divides the city of St. Louis into east and west halves. St. Louis to the west of the river is the core of the city and a white settlement. It is quiet and beautiful. Ancient buildings and modern buildings complement each other in the city. The Mississippi River is the fourth longest river in the world and the river with the longest flow, the widest drainage area and the largest water volume in North America. The main stream originates from the small Lake Itasca, 501 meters above sea level, in northwest Minnesota, to the west of Lake Superior, flows south through the central plains, and flows into the Gulf of Mexico.