CHICAGO MERCHANDISE MART - UNITED STATES


When opened in 1930, the Merchandise Mart or the Mart, located in Chicago, Illinois, was the largest building in the world with 4,000,000 square feet (372,000 mē) of floor space.[ The complex was renovated between 1986 and 1991 and now contains a shopping mall on the first two floors. The rest of the building contains showrooms where design professionals choose home and office furnishings

Link:
Wikipedia