The city’s developing. Let’s develop with it! The participative outdoor project BLAUSTELLE – ENTWICKLE DEINE STADT, which saw this appeal as a photographic product, invited participants to produce impressions of locations undergoing change as photograms and to make this urban change visible by showing the results as mobile exhibitions on construction fences. As abstract portraits of construction sites and the elements to be found there produced in situ, the photograms represented mementos of a temporary situation. Always along for the ride: MEL, the mobile development laboratory, the best friend of an audience that participated eagerly.