Meeting and preparation point: The group will be met at a pre-agreed meeting point, just outside the ravine. Here, a brief introduction and safety instructions will be given. Lamps and helmets will be given out, and all participants will be verified to be ready for the walk. Descent walk to the entrance of the tunnels : The adventure begins with a descent that will take you to the entrance of the tunnels. This hike offers a forest landscape and prepares you for the underground experience. Brief talk about the history of the place and what you will see next. Exploration and observation in the tunnels : Once at the entrance, a waiting point will proceed. Here, the calm of the night is interrupted by the amazing spectacle of the departure of the bats. After the observation, you will walk through a part of the tunnels, where the guide will explain the biology of the bats and the importance of their conservation. Emphasis will be placed on the unique aspects of this local species, its behaviour and its role in the ecosystem.