Île-de-France’s largest megalithic monument: 5,000 years of history under the open sky

Just a stone’s throw from Paris, a megalithic monument both intrigues and brings people together. In the Carnelle forest, the Pierre Turquaise imposes its inhabited silence and its history. Here, everyone can read a memory carved in stone.

La Pierre Turquaise, a Neolithic landmark at the gateway to Paris

Located in Saint-Martin-du-Tertre, Val-d’Oise (95), the Pierre Turquaise attracts the curious and families alike. The site lies some 35 km north of the capital. What’s more, the forest that shelters it makes for a soothing, hands-on visit.

Archaeologists identify it as a covered alley, i.e. a Neolithic collective tomb. Large slabs of local sandstone form a corridor and a chamber. The structure bears witness to precise, cooperative craftsmanship.

The site is open to visitors all year round, while respecting the tranquility of the surroundings. It is often described as the most important megalithic monument in the Île-de-France region, in terms of its scale and legibility. As a result, it serves as a benchmark for understanding regional prehistory.

“Faced with these stones, one feels the long time and the strength of a common gesture.”

Function, uses and traces of the past

The Pierre Turquaise was used for funerary and ritual purposes. Communities made collective deposits here, according to codified gestures. In this way, the site expressed both death and social cohesion.

Construction dates back to the Neolithic period, around the 4th millennium BC. The slabs weigh several tons, a sign of well-organized logistics. What’s more, this type of megalithic monument illustrates the sedentarization of the first farmers.

• Free access, site in the Carnelle forest, commune of Saint-Martin-du-Tertre.
• Covered driveway structure, visible and legible in the field.
• Neolithic period, several thousand years BC.
• Respect for the site recommended: no fires, no engraving, no climbing.
• Ideal for a culture-nature outing with family or friends.

Prepare your visit and enjoy the surroundings

Access is via well-maintained, signposted forest trails. By car, you can park close to the trailheads. The route is also pleasant in dry weather, with good footwear.

Spring and autumn offer soft light on the flagstones. In summer, the shade of oak and beech trees soothes the walker. Winter, moreover, reveals volumes more clearly, when vegetation becomes discreet.

The site has no permanent reception or ticket office. Bring water and a simple map of the area. In short, a self-guided tour is suitable for all, with caution for young children.

Practical advice on site

Please stay on the paths to preserve the fragile soil. Rocks must not be climbed or moved. In this way, everyone protects the stability of the boulders.

Photos are permitted, but no unauthorized drones. Choose a quiet approach, so you can hear the forest. What’s more, a few minutes of silence often changes your perception of the place.

Why this witness is a benchmark for the Ile-de-France region

La Pierre Turquaise helps tell the story of the long human history of the Île-de-France region. Its accessibility facilitates mediation by schools and associations. As a result, it acts as a public landmark for local prehistory.

Surveys and studies have refined our understanding of its shape. The site is part of a regional network of megaliths, more or less legible. As such, this megalithic monument serves as a benchmark for other sites.

The “Turquaise” toponymy appears in ancient sources, with spelling variations. We can see the persistence of a memory, rewritten by each era. In short, stone is as much a part of science as it is of the imagination.

Transmission, pedagogy and emotions

On site, it’s best to keep explanations simple and to the point. A map, a chronology and a sketch of the driveway are often all that’s needed. In this way, the visit becomes clear for all ages.

Feelings count as much as hard facts. Walking slowly, then observing the joints and supports, sheds light on the technical gesture. What’s more, this type of megalithic monument invites us to link past and present.

A heritage both discreet and powerful

La Pierre Turquaise is not a museum, but an encounter. The calm of the forest sets the scene for the mass of slabs. So the experience remains sober, concrete and memorable.

There are no spectacular effects, just architectural clarity. Volumes are organized in a legible way, from hallway to bedroom. As a result, the site remains intuitive to read.

Returning to different times of the year reveals other nuances. Rain darkens the stone, while the sun highlights the edges. In short, this megalithic monument always has a new way of showing itself.

• megalithic monument