The Merchandise Mart (or the Merch Mart, or the Mart) is a commercial building located in the downtown Loop, of Chicago, Illinois, United States. When it opened in 1930, it was the largest building in the world, with 4,000,000 square feet (372,000 m2) of floor space. The art deco landmark is located at the junction of the Chicago River's branches. The building is a leading retailing and wholesale destination, hosting 20,000 visitors and tenants per day as of the late 2000s.

Under Chris Kennedy's leadership of the Mart, it was the largest building in the world to be awarded LEED (Leadership in Energy and Environmental Design) Certification in 2007 from the United States Green Building Council (USGBC). The Mart has long been implementing sustainable practices. The Mart Center began operating a thermal storage facility in 1986, capable of building 2,000,000 pounds (910,000 kg) of ice per night, cooling 71 buildings in the surrounding neighborhood, and saving $200,000 in electricity costs in the first year.  In 1990, the Mart Center began using Green Seal-approved green cleaning products and the next year implemented a recycling program, which today includes all forms of paper products, glass, light bulbs, batteries, aluminum and construction materials. In 1996, the Mart Center became one of the first major property owners in downtown Chicago to enter into an agreement with the district cooling system now known as Thermal Chicago, thus contributing to the national effort to reduce the discharge of ozone-damaging CFCs.  In 2006, MMPI joined Clean Air Counts, a voluntary initiative to reduce smog forming pollutants and energy consumption in the Chicago area. Part of the campaign strategies included utilizing only low VOC cleaning products, paints and building materials, as well as energy efficient lighting and alternative workplace transportation options. To date, the Mart Center has reduced pollution by 264,018 pounds (119,757 kg), the largest reduction by a commercial building.  That same year, the Mart Center recycling program saved over 13,000 trees and recycled nearly 11 million pounds of waste, while water conservation efforts saved 5.5 million US gallons (21,000 m3) of water. More than eight percent of the estimated 10,000 people working at the Mart walk, bike or take public transportation; to encourage greener methods of transportation, the Mart expanded bicycle storage capacity to more than 200. In 2009, MMPI converted all stationery to a one hundred percent post-consumer recycled product.  The Mart has nine LEED-certified showrooms, with five others on their way to LEED certification.

What are some of the green building practices?
In 1990, the Mart Center began using Green Seal-approved green cleaning products and the next year implemented a recycling program,