German artists Bernd and Hilla Becher are a husband and wife team who often photograph European and American architecture. They spend a lot of time choosing their subjects, which include factories, natural gas storage tanks, grain elevators, and water towers. They like these ordinary structures and industrial buildings because of the way they look when many images of them are arranged together. For Wassertürme (Water Towers), nine towers with similar shapes were photographed during the same time of day at an almost identical distance. When they are placed in a grid, you can compare their forms and locations, and see the unique details of each.