Aven du Caladaïre

Aven du Caladaïre is one of France's deepest and most storied cave systems, hidden in the cliffs above a ravine in the commune of Montsalier, on the Albion plateau in the Vaucluse mountains (Alpes-de-Haute-Provence). It's a destination for cave-history enthusiasts and hikers exploring the Provençal backcountry — not a walk-in show cave.

What exactly is Aven du Caladaïre?

An "aven" is the Provençal term for a vertical karst shaft — a natural chimney in limestone through which rainwater drains into an underground system. Caladaïre plunges to a depth of roughly 667–668 metres, with about 1,850 metres of surveyed passages. Once the Rognons and Monopoly networks explored between 1984 and 1987 are factored in, the system's total extent is estimated at 2,000 to 3,000 metres. Hydrogeologically, the shaft belongs to the catchment of the Fontaine-de-Vaucluse, the famous karst spring fed by a watershed of more than 1,200 square kilometres spanning the Ventoux and Lure massifs.

Where does the name come from?

Local shepherds originally called the shaft "trou de l'Obœuf." The current name only dates to 1945, after human remains were found at the bottom of the first pitch. Locals attributed them to a road worker — "caladaïre" in Provençal dialect — who had vanished without a trace the previous century. That story still gives the site a slightly haunting edge.

How do you get there?

The shaft sits within the commune of Montsalier, close to the ruins of the old hamlet of Vieux Montsalier and a scatter of abandoned sheepfolds (bergeries). It's a stop on a well-known walking circuit that links the village ruins, the bergeries, and the gouffre itself, crossing the dry, stony slopes typical of the Albion plateau amid lavender fields and garrigue scrub. Starting from Montsalier or the Banon area gives access to marked paths. Bring sturdy hiking boots, water, and a map — most of the route is exposed, with little shade.

What will you actually see?

The shaft opening itself is a vertical well cut into the rock — dramatic to look at, but genuinely dangerous. Descending even the first few metres requires full caving equipment: ropes, cable ladders, and real underground experience. For the average visitor, the appeal lies in what surrounds it — views over the ravine, the ruins of Vieux Montsalier, and the wide panorama of the Albion plateau — plus the knowledge that you're standing above one of France's record-breaking sinkholes. Approaching the unguarded edge of the shaft is hazardous and strongly discouraged.

History and exploration records

The shaft already appeared on Marius Bouvier's map back in 1879. The first exploration attempts were made in 1942 by Boy Scouts from Apt, with further expeditions through the 1940s gradually revealing the extent of the system. The expedition of 15–25 August 1949 set a lasting record: 231 consecutive hours spent underground, the longest continuous stay of its kind at the time. During that same expedition, Geneviève Mazaud, of the Claude Sommer caving clan (Paris, EdF), set the era's women's world depth record for a single descent, reaching 487 metres.

When is the best time to visit?

Spring (April to June) and early autumn (September to October) are the best seasons for hiking around Caladaïre, when temperatures on the exposed plateau are manageable and, if timing aligns with nearby lavender fields, the landscape gets an extra splash of colour. Summer heat can be brutal on the stony, shadeless terrain, while winter can leave the paths muddy or icy.

Frequently asked questions

Can you visit Aven du Caladaïre without caving gear? No. This is an active vertical cave accessible only to experienced cavers with proper equipment — ropes, ladders, helmets. Casual visitors can only reach the surface area around it.

How deep is this sinkhole? Aven du Caladaïre reaches a depth of around 667–668 metres, making it one of France's deeper karst systems.

Where does the name Caladaïre come from? From the Provençal word for a road worker, after remains believed to belong to a missing labourer were found at the bottom of the shaft in 1945.

Are there hiking trails nearby? Yes — a popular walking route connects the ruins of Vieux Montsalier, the old bergeries, and a viewpoint at the gouffre, crossing landscape typical of the Albion plateau.