One of my favorite discoveries in Chicago is the Empire Ballroom inside The Palmer House. It's just up the stairs from the hotel's magnificent lobby and has a rich history most anyone working at the hotel will be willing to tell you more about.
This room with its shiny wood floor and opulent chandeliers is where Frank Sinatra used to perform. While the ballroom itself is beautiful, it's most interesting feature is what's hidden behind the mirrored wall in its corner.
Push on the last panel and you'll stumble into a dressing room where famous acts - including Sinatra - used to get ready to go on stage. Several autographed pictures are still hanging on the walls.