The Landmarks Preservation Council of Illinois – also known as Landmarks Illinois – is a not-for-profit organization founded in 1971 to prevent the demolition of the Dankmar Adler and Louis Sullivan designed Chicago Stock Exchange Building.
The founding mission was "to stop the demolition of significant buildings in downtown Chicago."
Landmarks Illinois was involved in a highly publicized preservation effort to save Mies van der Rohe's Farnsworth House from being dismantled and relocated from its original site along the Fox River.
Modern architecture enthusiasts from around the globe answered the call to donate funds, and the house was purchased at auction from Sotheby's on December 12, 2003.
A rare example of freestanding single family design by van der Rohe, the house is now operated by Landmarks Illinois and open to the public for tours.