It is important to find an appropriate yardstick for the planning, the building costs and the construction period of temporary structures. A further issue is what will happen to a development after it has served its purpose. The Crystal Palace in London, conceived by Joseph Paxton and Charles Fox for the Great Exhibition in 1851, is an early example of temporary modular construction. Not only did it demonstrate the potential of iron as a material for light, transparent exhibition buildings. Paxton also introduced industrial methods into the predominantly craft construction of his time. After the exhibition, the building was dismantled and re-erected elsewhere in an extended form for a further 80 years. (Thorsten Helbig, Hauke Jungjohann, Matthias Oppe)