From the start, they were rigorous, photographing in the grey early morning light, often from a distance, to show the scale of the towers and tanks against nearby buildings or objects. In one photograph of a cooling tower, a tiny street sign is visible in the foreground; in another, a row of what looks like miniature Christmas trees stand in the foreground.

Their approach soon became even more rigorous, with each structure being photographed from a similar angle on a large-format plate camera. The grids were arranged to highlight the formal similarities of each structure, which, as their images of water towers in Detroit show, was constant around the world – but also their looming, ominous presence.

The Bechers approached photography the way a botanist might approach the cataloguing of flora and fauna. Indeed, at the Arles Photography Festival this year in an illuminating group show, Typology, Taxonomy and Serial Photography, their work was contrasted to that of Karl Blossfeldt, who once said "the plant must be valued as a totally artistic and architectural structure". Alongside the equally rigorous August Sander, who photographed ordinary German people in a similarly detached way, Blossfeldt embraced a scientific style that approached pure classification. The Bechers are heirs to that way of looking.

....

Bernd Becher died, aged 75, in 2007. By then, his and Hilla's influence was widely acknowledged, not just in terms of their own work, which fascinated Stephen Shore as he began photographing America, but because of their roles as teachers at Düsseldorf's Kunstakademie, where their pupils included Thomas Ruff, Candida Höfer and Andreas Gursky.

But the Bechers' way of working belongs to the past now. This is a requiem for a lost world and shows that, through the passing of time, even that which was once considered purely functional and even ugly, can attain beauty when seen through the eyes of the most attentive photographers.