This very unplanned visit to the Osselle Grotto near Besancon in France was one of the most rewarding parts of our journey. The cave system is quite large spans many kilometers and although it has been known now for many years is still not fully explored. The grotto apparently contains bones from over 3000 bears, which must have lived there over the time. The colors and formations within the caves are fantastic.
The tour there takes over an hour and if you plan to visit make sure you remember the cave system maintains constant 11C, so dress appropriately.
The owners of the grotto also have an amazing mineral exhibit, which they open to the public just before the cave tour.
Explore my Oselle Grotto photographic gallery.