Gorges de la Bourne

A 19th-century balcony road carved into the cliffs of the Vercors gorges.

The D531 runs east from Pont-en-Royans up the Gorges de la Bourne toward Villard-de-Lans, scooped out of vertical limestone walls that rise hundreds of metres above the river. Past Choranche the road tucks under huge overhangs and through short tunnels, with the Goule Noire bridge marking the wildest stretch. It is a Michelin three-star route, tight and committing rather than fast. Mind the unlit tunnels, overhangs that catch tall vehicles, and rockfall onto a road with little room to swerve.