Arêtes de poisson

Arêtes de poisson is an underground gallery network beneath Croix-Rousse hill, consisting of two main passages with approximately 32 perpendicular side galleries. The system extends for more than two kilometers at depths ranging from 10 to 30 meters below ground level.

The tunnel system lay hidden until 1959 when a sidewalk collapse revealed its existence beneath the city. Authorities then sealed the entrances with concrete barriers to prevent public access and ensure safety.

The name comes from the fishbone pattern formed by the main passages and their side galleries. Locals have developed a strong connection to these tunnels, recently voting to preserve them through digital documentation and public education projects.

Public access to the tunnels is not permitted due to narrow passages, ladders, and uneven surfaces that pose safety hazards. However, visitors can explore the underground network through virtual tours available online.

The tunnel network branches into two northern extensions, each containing ten vaulted chambers and measuring around 300 meters in length. These additional passages reveal layers of underground complexity that remain partially unexplored to this day.

Location: 1st arrondissement of Lyon

Website: https://aretesdepoisson.lyon.fr

GPS coordinates: 45.77310,4.83647

Latest update: December 6, 2025 16:02