The Main Branch of the Detroit Public Library opened in 1921, a Beaux-Arts marble building by Cass Gilbert (architect of the U.S. Supreme Court). The interior is one of the finest civic spaces in the city, with mosaics, murals, marble floors, and a soaring reading room. Pewabic tile is set into floors and fireplaces throughout. Two later wings added more reading rooms in matching style.
The building sits opposite the Detroit Institute of Arts on Woodward Avenue and is open to the public. The Burton Historical Collection, on the second floor, is a major resource for Michigan and Great Lakes history. Free.