The 4,000-seat theater, which today is the scene of such major Broadway musicals as Showboat and Les Miserables, is a marvel of visionary design and engineering. Originally the home of the Chicago Opera Company, Sullivan's and Adler's masterpiece is a glittering display that makes King Midas look like a piker. Defined by powerful arches lit by thousands of bulbs, and featuring Sullivan's trademark ornamentation--in this case, elaborate golden stenciling and gold plaster medallions--the theater positively glows on performance nights. It's equally renowned for otherworldly acoustics and unobstructed sight lines. Supposedly, a person seated in the top gallery can hear an unamplified whisper on the stage six floors below. In the days when the Auditorium was the leading theater of Chicago, the hydraulically operated stage could be lowered from view, creating a ballroom capable of accommodating 8,000 guests.

Owned since 1946 by Roosevelt University, the Auditorium has had a roller-coaster history. Originally the site of a 400-room luxury hotel and commercial office space, it fell on hard times during the Depression and closed in 1941. During World War II, the building sheltered GIs and its theater stage was turned into a bowling alley. The theater reopened in 1967 following a $3 million renovation made possible through the fund-raising efforts of the nonprofit Auditorium Theatre Council, but in recent years the council has battled Roosevelt University in a series of acrimonious court cases over proprietorship and revenues. Remnants of the building's halcyon days remain. Don't miss the lobby fronting Michigan Avenue, with its faux ornamental marble columns, molded ceilings, mosaic floors, and Mexican onyx walls. Another inside tip: Take the elevator to the school's 10th-floor library reading room and have a look at what was once the city's first top-floor dining room. Its palatial, barrel-vaulted, muraled ceiling and marvelous views of Grant Park and the lake will make you want to brush up on your Dewey Decimal System.