Since 1959 Bernd and Hilla Becher have been photographing imperiled industrial structures such as pit-head frames, water towers, blast furnaces, cooling towers, gas tanks, and silos. As documenters of the industrial era in Europe and the United States - an era now drawing to a close - they are not only photographers, but industrial archaeologists, salvaging testimonies of past developments in the form of readable documents for posterity. At the same...