(for the non-Chicagoans: The Chicago River cuts through downtown Chicago and is home to the most moveable bridges in the world for any city. The river is a constant green color and is said to be extremely dirty as it was a dumping ground in the early 20th century for dead animals and waste. In fact even to this day if the sewers get backed up downtown, they overflow to the Chicago River. Hence why nobody would ever want to swim in it)
Are there any major cities in the world with a river running through the middle of it that people swim in and has beaches that are clean?