UNESCO has placed the Lower German Limes on the World Heritage List. Previously UNESCO included the New Dutch Waterline and the Dutch Colonies of Benevolence.
The Limes is the largest archaeological monument in Europe. The Limes consisted of a system of forts, watchtowers and roads. In the Netherlands, the Romans built 20 forts (castella) on the south bank of the Rhine. In Utrecht, too, the Romans built a fort, the castellum Trajectum, at the location of the current Domplein Square. The Domplein Foundation commissioned OKRA to design a marker for the Roman castellum wall to make the origins of Utrecht visible on and around the Domplein Square.
The design consists of a small intervention with great significance. The underground castellum wall is marked in the street plane by a single line of corten steel elements, directly above the original Roman wall. Coloured light and patches of mist emanate from the marking, and parts of the borders of the Roman Empire are engraved in the steel. The smoke intensifies into a fog curtain on special occasions and holidays, making the transition to Dom Square even more dramatic. In rain or foggy weather and after dark, the line is even more visible.