Going Underground

We went to the Grottes de Betharram today near Lourdes. It was first opened with electric illumination in 1903. I would love to have been one of the first people in there exploring with a torch before it was turned into a tourist attraction. That said it has been very well done and tastefully illuminated on the whole , except for a rather naff train ride out of the caves at the end of the tour.
The caves have been carved out by the river over millennia and have left these astonishing shapes and stalagmites and stalactites.