Considered by many historians as the first example of modern architecture, the house was designed by Louis Sullivan and Frank Lloyd Wright. Constructed in 1892, the building was marred by an addition built in 1924, as well as neglect. John Eifler served as project architect while employed by Skidmore Owings and Merrill, who purchased the house to serve as their headquarters for the SOM Foundation. The addition was removed and the south elevation was rebuilt. A new copper roof and skylight installed, and exterior masonry window openings were returned to their original configuration. The interior plaster finishes were completely reconstructed, and all woodwork preserved and refinished. New mechanical, plumbing and electrical systems were installed throughout. The Charnley House is a National and City of Chicago Landmark and now serves as the headquarters of the Society of Architectural Historians.