This is some of the amazing stone work on the back corner of the Rookery Building. Each corner of the building has the names of the cross streets carved in, I think, terra cotta. It's a very famous building, designed by Burnham and Root in the style that became know as the Chicago School. It is one of the first "skyscrapers," and is the oldest standing high-rise in the city. Built in 1887-88, the lobby was remodeled in 1905 by Frank Lloyd Wright. In 1989 the lobby was restored to Wright's remodel.
The main entrance of The Rookery faces LaSalle Street. Rookery Court is a little one-block street off Adams Street, at the rear of the building.