Baume de Ronze

La Baume de Ronze is a dramatic collapsed sinkhole on the Saint-Remèze plateau in the commune of Orgnac-l'Aven, in the southern Ardèche — a short walk from the world-famous Aven d'Orgnac cave and its Prehistory Museum. In the old Occitan dialects of the region, "baume" simply means a rock shelter or cavern, and that word choice fits: what remains here is a huge sunken chamber, part cave, part open-air crater, shaded by a surviving stretch of ancient cave roof.

What exactly are you looking at?

Baume de Ronze began as an underground gallery carved by a river running through the limestone plateau. As the climate shifted over tens of thousands of years, that river cut its channel deeper into the rock, leaving the older, higher gallery dry and abandoned above it. Without running water to support it, the ceiling of that upper gallery slowly weakened as rain and seepage worked through the stone, until a large section finally gave way. The collapse left a wide, open gash in the ground tens of metres across, with a sizeable rock shelter — well over a thousand square metres of sheltered floor space — surviving underneath the section of vault that never fell in. It's this dry, protected shelf that gives the site its real significance.

Why does this spot matter to archaeologists?

Long before it was a hiking stop, the shelter at Baume de Ronze was a home. Excavations carried out here across roughly two decades, from the late 1970s into the mid-1990s, uncovered occupation layers stretching from the late Upper Palaeolithic all the way through the Neolithic period. Each layer tells its own story of a changing climate — a warmer spell early in the Neolithic, conditions not unlike today's in the middle Neolithic, then a wetter phase toward its end — and of the people living through those shifts, including the arrival of pottery-making and the first steps into farming and animal husbandry in the region. A reconstructed cross-section of these layers is now on display at the nearby Orgnac Prehistory Museum, giving visitors a way to connect the empty shelter with what once happened inside it.

How do you actually visit, and what should you plan for?

A signposted walking loop of roughly 5.9 km links Baume de Ronze into a route that takes about two hours to complete. It's graded as an easy walk, though it does climb a cumulative 168 metres and tops out at 363 metres above sea level, so it's more of a countryside ramble than a stroll. The trail sets off from the information panel at the entrance to the Aven d'Orgnac visitor site, then crosses a garrigue-covered plateau scattered with limestone pavement, further sinkholes, and dolmens, with stretches of shade under oak woodland along the way. The loop stays open all year, and downloadable maps in PDF, GPX and KML formats are available for anyone navigating by phone or GPS; the Gorges de l'Ardèche – Pont d'Arc tourist office can answer further questions.

Frequently asked questions

Can you go down inside Baume de Ronze the way you can at Aven d'Orgnac? No. Unlike its famous neighbour, which is developed for guided underground tours, Baume de Ronze is an open, partly collapsed karst feature that you view from the surface and from the walking trail, not a show cave with managed access below ground.

How long should I set aside for the walk? Budget around two hours for the full loop at an easy pace, plus extra time if you want to linger at the viewpoints and information panels along the way.

Is the trail suitable for families? It's rated easy, but at nearly 6 km with some climbing, it's worth judging younger walkers' stamina beforehand. Much of the route crosses open garrigue scrubland with little shade, so carrying water is a sensible idea in warm weather.

Where can I see what was found during the excavations? The excavated stratigraphy and finds are presented at the Orgnac Prehistory Museum, right next to the trailhead, making it easy to pair a visit to the museum with the walk itself.