skyscrapers along the river

Chicago, Illinois - USA

The Chicago River originally flowed into Lake Michigan, but due to high levels of pollution and the water supply being threatened, it was decided to reverse the flow of the river by building a series of canals.  This river eventually connected with the Illinois River which in turn connected with the Mississippi River flowing all the way to the Gulf of Mexico.  The Chicago River turned out to become an important link between the Great Lakes and the Mississippi River Valley.