They make pumps and pump controls; they sell pumps, rep pumps, service pumps, and engineer pumping systems ranging from small to humongous.
Most of us, out-of-towners and natives alike, never get to see beyond the facades and activities taking place inside these attractions. Exceptions include a few thousand people associated with the Chicagoland plumbing and mechanical industry. These folks hang out in the bowels of these facilities to install, maintain and service the equipment that keeps water flowing for comfort and convenience - or, in the case of Buckingham Fountain, just for show. All of them deal in some manner with the products and personnel of Metropolitan Industries, a company involved with just about every prestige project one can think of in the Chicago area.