Lake Serre-Ponçon shapes the opening kilometres, with broad stretches of water and the small Saint-Michel chapel on its rocky islet. The bridge at Savines carries the route across the lake before the road climbs above the shore towards Le Sauze-du-Lac. Beyond the Ubaye arm, it follows the valley upstream to Barcelonnette. The climb to the Col de la Cayolle begins along the Bachelard, where a narrow gorge squeezes the road between rock walls, woodland and small hamlets. Higher up, trees give way to mountain grassland and stony slopes. At 2,326 metres, the pass links the Ubaye valley with the headwaters of the Var. Successive bends descend through the mountains by the Mercantour to Entraunes, a cluster of stone houses at the end of a roughly 98-kilometre day.
