First of all, they dye the Chicago River green. It's pretty impressive, as you can see in these photographs from a 2007 visit to the Windy City. The view above is from the North Michigan Avenue Bridge looking along the river east towards Lake Michigan.

The river has an interesting engineering history. When European settlers first occupied the land here, the river flowed east into Lake Michigan. But when the famous stockyards developed in the late-1800s, the carcasses flowed into Lake Michigan and threatened to pollute the city's drinking water source. So the river was artificially elevated and made to flow west into the Chicago Sanitary and Ship Canal, thereon to the Des Plains River, and eventually to the Mississippi River. This way, nasty organic debris flowed west to the Mississippi and did not foul Lake Michigan. Instead, the debris had the opportunity to foul St. Louis and Baton Rouge. The map above is from Wikimedia Commons.
The historic stockyards are closed and the dead cows long gone. The river is still a Federal navigation project but now mostly carries tourist boats, pleasure craft, and water taxis through the city. To gain access to the river from Lake Michigan, boats have to enter locks and be raised a few feet (the amount varies depending on Lake level, which varies throughout the year). The Sanitary Canal to the south carries significant commercial barge traffic. The view above is from Michigan Avenue looking west.
Finally, the big parade. You see hundreds of policemen in formation, floats from fraternal organizations from surrounding states, and high school bands. I am not sure how you get to march; I suppose fill out an application and pay a fee. A good time is had by all.
For a summertime view, here is the Chicago River looking east towards Lake Michigan. This photograph is from the 34th floor of the Hyatt Regency Hotel. If you are really rich, the condominiums in this area are pretty spectacular.
The mouth of the Chicago River is protected from storm waves by breakwaters.
This is the prosperous Gold Coast. my photographs from South Chicago fit my theme usual of urban decay more closely than the glamorous c entral city.
All photographs taken with a Sony DCS-W7 digital camera except for the 1996 scene, which is a scan of Kodachrome film.
