Gorges du Guiers Vif, Natural canyon in Chartreuse Mountains, France.

Gorges du Guiers Vif is a limestone water gap carved by the Guiers Vif River through the Chartreuse Mountains, creating deep channels and narrow rocky passages. The mountain road passes directly through these confined sections, featuring some unlit tunnels and sheer rock walls on both sides.

The limestone was carved by flowing water over millions of years, creating this mountain passage. The modern road D520C was constructed in 1994 to connect two previously isolated valleys directly through the gorge.

The gorge takes its name from the Guiers Vif River that flows through it. People come to experience the raw power of water shaped over centuries within these steep walls.

Driving through the gorge requires attention due to darkness in some tunnel sections and the narrow road layout. It is advisable to drive slowly and use headlights to navigate safely through this mountain passage.

The old road clung to a bridge fixed to the cliff before the D520C was built; its remains can still be seen from the bottom of the gorge. The passage through the tunnels is called Pas du Frou, from a local term meaning "fearsome passage".