A quiet single track road following the river through the Riera de Merlès Protected Natural Area. Climbing gently from south to north, you leave behind farmland at 550M above sea level, and progress through paddocks and homesteads, passing the occasional small campsite, before emerging in a wooded valley at 800M, joining the BP-4654. Discovered on a ride from Sant Cugat del Vallès to Escot in the Pyrenees.