The art deco Chicago Board of Trade Building in downtown is a mainstay of architectural tours. Pictured is the mechanical beauty of the vault, part of the original 44-story North Building designed in 1930 by Holabird and Root. In 1982, Murphy/Jann Architects designed the 22-story South Building addition. The compound totals a combined 1.3 million square feet of rental space. Location: 141 W. Jackson Blvd.