Nouvelle-Aquitaine is a result of the merging of Aquitaine, Limousin, and Poitou-Charentes in 2014. This region is much too large with too many underground sites and its parts have completely different geologic units. There are the mountains of the pyrenees in the south, the Aquitaine Basin, and the limestone plateaus of Dordogne and Lot et Garonne. So we split the region into its political parts and added a fourth section for the Vézère Valley, which is not a political but a geographical unit.