Air conditioning
Modern air conditioning emerged from advances in chemistry during the 19th century, and the first large-scale electrical air conditioning was invented and used in 1902 by US inventor Willis Carrier. The introduction of residential air conditioning in the 1920s helped enable the great migration to the Sun Belt in the United States.
Famous-Barr
Famous-Barr was created in 1911 through the merger of The William Barr Dry Goods Co. and previously May-owned The Famous Clothing Store. Famous-Barr was the first air conditioned department store in the United States. The store opened in Downtown St. Louis in 1914.