The french Jura covers the two departments of Doubs and Jura and boarders at the east side to the french speaking part of switzerland. The sparsely populated area is impressing by its big forests, sharply incised valleys, lonesome highlands and summit hights of around 1600 m.
The area provides fine food with the well known "Comté" cheese and superb white wines.
But even better is the underground of this huge limestone area. There are unbelievable numbers of caves. Among them, important names like the Verneau system or the Borne aux Cassots.
A huge number of caves in the area feature active parts (so called Collecteurs) and can only be visited at appropriate weather conditions.
Therefore, the area is best visited at the cold time of the year, when the temperatures are constantly below 0.