The D952 Route des Crêtes encircles Europe's Grand Canyon — a 700 m-deep turquoise gorge carved by the Verdon River through limestone plateaux in Provence. The road clings to the rim with no guardrails on significant sections. The emerald Lac de Sainte-Croix at the western end is the reward.
Clone it to your planner, customize dates and stops, then ride. All free.