Réseau de l'Alpe

The Réseau de l'Alpe is a cave network in the Chartreuse Mountains that spreads through limestone formations connecting multiple underground chambers and passages. The various cavities and tunnels form an elaborate maze extending significantly below ground level across a wide area.

Exploration of the system began in the 1940s with the Biolet Cave, which early explorers reached at considerable depths. Systematic expeditions followed, gradually revealing the extent of the network and discovering new passages over the following decades.

The network includes 37 main entrances and represents a significant destination for French and international cave exploration communities.

Visitors should prepare for uneven terrain and damp conditions, as the underground environment remains constantly wet and can be slippery. Proper lighting and sturdy footwear are necessary to navigate safely through the various passages and chambers.

An underground river called the Jade flows through the connected cavities and creates an aquatic landscape within the massive limestone formations. This water system makes exploration dynamic and shows how water has shaped this rocky landscape over millions of years.