Start off big with one of the largest underground halls in France. Located 20-kilometers (12.42 miles) from Besançon, the Gouffre de Poudrey (nicknamed the "Underground Cathedral") could indeed fit the Notre-Dame-de-Paris inside it! A series of stairs leads down to 70 m (230ft) underground. During the descent, one can imagine encountering the legendary Vouivre, a mythological dragon-like animal with the bust of a woman and a body of a snake, who's said to guard the place. You may also need to bring along a sweater beacause of the temperature, which is around 7°C (45°F).
Located near the Arc-et-Senans salt works, the Osselle cave was the favorite den of the cave bears. In 1856, the first skeleton of this 2.5m (over 8 foot) high prehistoric animal was discovered in the depths of this cave. In the seventies, some fifteen entire skeletons were also discovered, making the Osselle cave the greatest known burial place of cave bears in Europe. The chasms are also well known for their multi-colored walls, dyed from the minerals in the water. With 15 halls, the cave contains a 1,200-meter (nearly 4000 foot) main gallery crossed by a tributary of the Doubs river.
At the end of the Baume-les-Messieurs blind valley, a typical geological phenomenon of the Jura region which features a flat-bottomed valley with an abrupt end, you can find the eponymous caves. Escorted by a guide, you can wander through a 1-kilometer (.5 mile) gallery punctuated by 20 to 80-meter (65 to 262 feet) high halls. The caves hide an underground lake and the Dard river, the source of the Baume-les-Messieurs waterfall. Impressive as the caves are, they are not the only draw of this pretty village, listed as one of "The Most Beautiful Villages of France." Do not miss the town's imperial Benedictine abbey, its charming architecture, and the panorama surrounding this valley nestled inside a limestone plateau.
Discovered in 1966 and open to the public for 20 years, the caves of the Moidons offer modern infrastructure that allow easy accessibility to all. After a presentational film, you can descend and discover the cavity formed during the Ice Age, where stalagmites, stalactites, columns, and odd formations are highlighted by light and sound show. The visit ends by a tour of the bat cave labyrinth, designed for kids.
It's always cool in the Cerdon caves, which were used by Prehistoric peoples to keep their food fresh, and then by cheesemakers to refine their product in the thirties. Nowadays, you can explore them from their depths to the surface by walking through the bed of an old underground river. This guided tour allows you to understand the key role of water in the creation of these cavities. Back to the surface, you can continue the visit to the gazebo above the Cerdon vineyards and to the impressive porch, which is a must-visit at the end of the caves. The Cerdon caves also organize Prehistoric activities to complete your underground visit. Introductions to fire techniques, archeological digs or Prehistoric painting are held in the park next to the caves.