The venerable Dallas International Apparel Mart, the 40-year old national institution that once bustled with energy and acted as a driver for many apparel businesses, is set to close next year.

During the next 14 months, 1 million square feet of the nearby World Trade Center will be reconfigured to hold the 600 showrooms of the Apparel Mart.

The move will leave 1.8 million square feet of empty space at the Apparel Mart.

The fate of many apparel marts across the country is the result of a long-term shift in the way stores buy merchandise as well as the consolidation of retail and the reduction in small specialty retailers.