The “Arêtes de Poisson” underground tunnel network explained in English
Walid Nazim’s 2011 “L’énigme des Arêtes de Poisson” has been released in English under the name of “The Secret of Lyon’s Fishbones.” The book chronicles the history and theories behind one of the city’s most secretive networks.
Under the hill of Croix-Rousse the Fishbones tunnels remain closed to the public
The Fishbones are a network of 32 parallel tunnels, also called galleries, that are all dead-ends. Sitting under the hill of Croix-Rousse, the tunnels remain unknown to many of Lyon’s residents and visitors, closed to the public since their discovery in 1959.

Nazim is an expert on Lyon’s underground Fishbones network and has his own theories about where it came from. © Walid Nazim
“It’s called the Fishbones because the city workers nicknamed it that when they had the plan of it,” explained Nazim, who has spent his life exploring Lyon’s underground tunnels. “When they explored it they didn’t even know what it looked like, and they found 32 galleries that are dead-ends after 30 meters.”
Few archeological studies have been done on the tunnels
The Fishbones are one of Lyon’s most unstudied monuments. Dated from the 16th century and then re-dated from antiquity, it is unclear where this network came from or what purpose it served.

Lyon famous Arêtes de poisson underground network.
Few archeological studies have been done on the tunnels and Nazim explains that the city has little interest in preserving the network or making it widely known. Nazim’s book, originally published in French, has been translated into English to allow wider access to the mystery.
“This is exactly why I published a book in English,” he said. “People here, they’re like, ‘It just interests people who like tunnels and are Lyonnais and it’s just something that is local.’ But this is crazy. It’s like thinking that the Pyramid of Giza is just for Egyptians.”
Nazim’s second book in the Fishbones series is scheduled for release in summer 2019. He also offers guided tours of the area above the Fishbones, in English and in French. Email walid.nazim@aretes-de-poisson.com for more information and to schedule a tour.