It is the oldest tourist site of the village of Trôo. Already open to the public at the beginning of the 20th century, this small space dedicated to the long work of limestone waters, is interesting not only for tourists, but also from a geological point of view. You can discover stalactites, the remains of the old chapel Saint-Gabriel, its petrified basin and all the magnificent work of water on the tuffeau (local limestone) in 300 years.
The cave has significant water resources. This water from various sources, the exact origins of which are unknown, flows from the centre of the Butte, which is extremely loaded with limestone. The Loir valley was, 90 million years ago, an immense inland sea from which the cavities were dug throughout its bed.
Why are you petrifying? Water charged with carbon dioxide dissolves the limestone of the rocks it passes through and, when it comes into contact with the warmer air of the cavities, it deposits the transported calcite. It accumulates in stalactites where the water comes off the ceiling or in stalagmites where the water drops on the ground.