There is an ongoing urban revitalization project for Domplein or cathedral square of the city of Utrecht by OKRA Landscape Architects. This is where Utrecht began, 2000 years ago, with a Roman castellum that now lies 4 metres underground. After 2000 years of history, today the Domplein is a shabby, cold and draughty square and the city is planning to transform it into a beautiful plaza, a place to be proud of. It is being altered, in a number of small steps, the first concrete intervention in this transformation is the marking of the currently underground castellum wall, the boundary of the future square.
This guardian line is marked with Corten steel elements at street level, directly above the original castellum wall. Its width, 80 cm, is as wide as the wall, and makes the transition from the profiled streets to the flat square floor. Green light and wisps of mist emanate from the marking and the borders of the Roman Empire are engraved in the steel. The marking is just as silent as the archaeological witness underground.