As Friends of the Chicago River celebrates its 40th anniversary, we highlight 40 people who have contributed to the improvement of the Chicago River system.

Friends of the Chicago River and the Illinois Department of Natural Resources reconnected Mill Creek with the Cal-Sag Channel nearly a century after the canal was built.

Recent rains forced 85 combined sewage overflows into the Chicago River system.

"We can and should become an international leader in urban greening," says Friends' Executive Director Margaret Frisbie.

Friends' Original Earth Day River Cruise aboard Wendella Boats explored the successes and challenges facing the Chicago River.

 "The Chicago River defines Chicago's past. It's going to define Chicago's future," said Mayor Rahm Emanuel.

Friends helps "keep this agency on track and honest and we have a great partnership," said Commissioner Debra Shore.

Sparked by a 1979 magazine article, Friends of the Chicago River plays a key role in the renaissance of one of urban America's greatest natural gems.

This year's sold-out professional conference focuses on a connected waterway.

A return on investment on developing the Chicago River as a blue/green corridor would return $1.77 for every $1 spent, the University of Wisconsin-Whitewater report finds.