You are looking for a magnetic container in a scenic spot overlooking the Chicago River. Be sure to give a friendly wave to passing boats, but beware of watchful tour operators. Please replace cache exactly as you found it. Bring your own writing utensil.
In 1900, the Chicago Sanitary District completed a man-made hydrologic connection between the Great Lakes and Mississippi watershed by reversing the flow of the Main Stem and South Branch of the Chicago river using a series of canal locks, and increasing the river's flow from Lake Michigan, causing it to empty into the new Canal. In 1999, this system was named a 'Civil Engineering Monument of the Millennium' by the American Society of Civil Engineers (ASCE).
The source of the South Branch of the Chicago River is the confluence of the North Branch and Main stem at Wolf Point. From here the river flows south passing the Lake Street, Randolph Street, Washington Street, Madison Street, Monroe Street, Adams Street, Jackson Boulevard, Van Buren Street, Congress Parkway, and Harrison Street bridges before leaving the downtown Loop community area. Notable buildings that line this stretch of the river include the Boeing Company World Headquarters, the Civic Opera House, the Chicago Mercantile Exchange, Union Station and Willis Tower.