The pact that linked it to the real from its birth was guaranteed by the technique itself. Today that is no longer the case: photography has moved on from that stage, gaining freedom and losing innocence. Born in Germany in the 1930s, Bernd Becher and his wife Hilla set out on a strange undertaking: to create a photographic inventory of industrial buildings that were destined to disappear, such as water-towers, silos and blast furnaces. In the space of 30 years, the "Dusseldorf School ", the Bechers and their "pupils " - Candida Höfer, Petra Wünderlich, Thomas Struth, Thomas Ruff and Andréas Gursky - were to radically transform photographic practice. They retained a few key characteristics from the Bechers' teachings: attention to distance, apparent objectivity, and a predilection for straight lines. But each of these photographers reinterpreted this model and developed their own photographic universe. For some, colour became a tool to reinterpret the real, while others remained faithful to black and white. All of them produced very large prints. Photography was no longer a simple document, it was a work in its own right, able to rival the paintings that hung on museum walls.