Driving Inside the Earth: Grotte du Mas d'Azil Is the Only Road Through a Cave in France

Located in the Ariège department in southwestern France, the Grotte du Mas d'Azil is a 500 metre long tunnel dug by the Arize River in the Ariege Pyrenees. It is the only cave in Europe that can be crossed by car.

Grotte du Mas d'Azil

Route Nationale 119 (or RN 119) passes through the central section of the Mas d'Azil Cave. The road runs right through the large cave, which is a natural tunnel 420 metres long and 50 metres high. This cave was long a refuge both for animals (rhinoceros, bears and mammoths) and humans (from the Magdalenians to the Huguenots).

The speed limit inside the cave is 30 km/h. Forbidden to cars 3m height. The asphalted road is a nightmare for people suffering claustrophobia. Although there is lighting at the edge of the road, cars are required to turn on their headlights when entering the grotte. 

The Tour de France race passed along the cave. While it is possible to cross the cave by car, there is no possibility to park the car inside the cave. The parking lot is in front of the cave portal, and there is a footpath into the cave, along the road.