There are many places to go and experience nature in and near the city, from the gorgeous lakefront to Northerly Island, North Park Nature Center, the Lincoln Park Zoo and Garfield Park Conservatory, the Chicago River (canoeing and kayaking) in the city proper, to large forest preserves immediately surrounding the city, and much more in the greater Chicagoland area
http://www.cityofchicago.org/city/en/depts/doe/provdrs/ccgt.html The Center for Green Technology (CGT), Sacramento and Lake.
CGT has classes for professionals and novices alike, a resource library, and a wonderful self-guided tour.
“The Chicago Center for Green Technology is the first rehabilitated municipal building in the nation to receive the Leadership in Energy and Environmental Design ™ (LEED) Platinum rating by the U.S. Green Building Council. Mayor Richard M. Daley dedicated the building in 2002 and it has since become a national model for sustainable design and technology. The Center serves as the most comprehensive green design and educational resource in the Midwest.”
http://www.foresightdesign.org Foresight Design Initiative is a great hub for all things, people, and organizations related to sustainability in Chicago. Check out their ‘events’ tab for lots of events, from training to panel discussions to movies on environmental topics.