Like a slipcover over a sofa, the clean, geometric facade of this1895 building expresses what lies beneath: in this case, a structural steel frame. Sure, the base is marked with roughly cut stone and a fancy cornice crowns the top, but the bulk of the Marquette Building mirrors the cage around which it is built. Inside is another story. The intimate lobby is a jewel box of a space, where a single Doric column stands surrounded by a Tiffany glass mosaic depicting the exploits of French Jesuit missionary Jacques Marquette, an early explorer of Illinois and the Upper Midwest. From its steel skeleton to the terra-cotta ornamentation, this Holabird & Roche structure is a clear example of the Chicago style.