Le Monolithe de Sardières, Sedimentary rock formation in Val-Cenis, France

Le Monolithe de Sardières is a free-standing rock column made of vacuolar dolomite, rising about 93 meters above the surrounding terrain at an elevation of roughly 1670 meters, in Val-Cenis, France. It stands alone, narrow and vertical, giving the impression of a natural stone tower placed in the middle of the mountain landscape.

The spire is made of cargneule, a compact dolomitic limestone that resisted erosion while the softer surrounding rock was worn away, leaving the 93-metre column standing. On 26 June 1965 the opening ceremony of the Vanoise National Park was held at its foot. Michel Paquier made the first ascent in 1957.

The monolith stands near the edge of the Vanoise National Park and is seen as a landmark of the Haute-Maurienne valley. It is visible from many trails in the area and serves as a natural reference point for hikers moving through the mountains.

A marked trail leads to the base of the column starting from a parking area below, with a steady uphill walk that takes a couple of hours. Sturdy footwear is recommended, and it is worth setting off early to have enough time for the return.

Although the column looks solid from the outside, the dolomite it is made of is full of tiny internal holes, which is what the word vacuolar means in this context. This porosity makes the rock lighter without making it any less resistant to the erosion that shaped it.