The River Ourthe is born of the confluence near Nisramont of two tributaries: a western one which rises near Ourthe in Luxembourg, and an eastern one which begins at Ourt to the south of St-Hubert. Upstream from La Roche-en-Ardenne, it is fast-flowing through a wild and beautiful landscape. From La Roche-en-Ardenne to Liège, the Ourthe Valley is gentle and pleasant, with occasional rocky outcrops and limestone caves.