The thirteenth-century water castle of the archbishops of Trier, originally surrounded by the Moselle on three sides. The medieval core is still recognisable behind a Renaissance and Baroque facade; the building now houses the city archive.
Walk round the back, where the original twin round towers face the Moselle, for the best view of the medieval fabric. The riverside path runs from here to the Baldwin Bridge and back to the Deutsches Eck.