Once a place of open-air extraction, the basin was covered with a vault in the nineteenth century and since then, this crypt was completely filled with salt water.
After the evacuation of this salt water and important works, the crypt can now be visited. This descent under what has become the main square of Salies-de-Béarn allows to enter a space where the play of light highlight a construction never unveiled so far.
It is also an opportunity to talk about the history of salt water exploitation for more than 3,000 years.