Credit: Eileen Mesler

Today the magnificently ornate terra-cotta skyscraper that overshadows every other structure on the river, including the way more famous Wrigley Building and Tribune Tower, is an office building known, rather prosaically, by its address, 35 E. Wacker Drive. But when it first went up, back in 1926, it was known as the Jewelers Building and it was, essentially, the city’s tallest parking garage. Jewelers carrying thousands of dollars worth of diamonds and justifiably concerned about robbery could drive their cars into the building from Lower Wacker, where elevators would spirit them—still in their cars—up to their offices.

But that wasn’t even the coolest thing about the Jewelers Building. That would have been the 40th-floor cupola, accessible by an ornate birdcage elevator, which housed the Stratosphere Lounge. Some architectural historians describe it as a “restaurant.” But come on. Al Capone was a regular and, it was rumored, the owner.

Now the 40th floor is occupied by the architectural firm Murphy/Jahn, which uses the curving walls and ceiling and the spectacular views as a backdrop to show off its finest projects. If you’re not a client, you’ll have to wait till October to see it, when it’ll be a stop on the Chicago Architecture Foundation’s Open House Chicago tour.