The clearly expressed, gleaming verticality that characterizes the modern skyscraper was first and most eloquently articulated in this trailblazing steel-frame tower, built by Burnham, Root, and Charles Atwood. Completed in 1895 and now home to the stylish Hotel Burnham, the building was a crumbling eyesore until the late 1990s, when the city initiated a major restoration. In the early and mid-1900s, it was a mixed-use office building. Al Capone's dentist reportedly worked out of what's now Room 809. Don't be misled when you go looking for this masterpiece—a block away, at State and Randolph streets, a dormitory for the School of the Art Institute of Chicago shamelessly mimics it. Once you've found the real thing, admire the mosaic floor and ironwork in the reconstructed elevator lobby. The building boasts early examples of the Chicago Window, which define the entire facade by adding a shimmer and glimmer to the surrounding white terra-cotta.