Lyon’s Fishbones: The Forbidden Underground Tunnels of Croix-Rousse

An underground tunnel network the city is determined to keep hidden


The Fishbones is an underground tunnel network running under the Croix-Rousse hill in Lyon’s 4th arrondissement. Discovered in 1959, the Fishbones are a mystery of Lyon the city would rather forget.


Cars and buses whizz through the Tunnel de la Croix-Rousse under Lyon’s 4th arrondissement. People bike, walk, and run through the pedestrian entryway, added to the network in 2013. To the side rise massive stone walls, marked by two slightly decayed alcoves unnoticed by passersby.

But behind the alcoves hides another story, one still unfinished: the story of Lyon’s underground tunnels, and the underground missions that created them. For the few who know they exist, these tunnels are called the Fishbones.

walid nazim in the fishbones of lyon

Author Walid Nazim has dedicated years to understanding the history of Lyon’s Fishbones. © Walid Nazim

“You have these two little [alcoves],” explains Walid Nazim, author of the book L’énigme des Arêtes de Poisson and its English version, Lyon’s Fishbones. “Nobody knows what it is. Nobody’s going to wonder what it is because it’s just two little marks. But beside it there’s the whole mystery.

Lyon’s Fishbones are an underground network of tunnels, spanning the depths of the Croix Rousse hill and connecting to the Sarrasinières tunnel network that runs to Miribel in the North. 32 parallel galleries, created seemingly without cause and without explanation, which make up one of Lyon’s best-kept secrets.

“It’s not just an underground, it’s an underground monument. And you won’t hear about Lyon’s tunnels because it’s not part of the official ‘patrimoine,’” said Nazim. “The city refuses to talk about it.”

So the Fishbones remain closed to the public and unprotected from decay, with the Tunnel de la Croix-Rousse and future public works projects threatening to destroy the remaining proof of Lyon’s greatest mystery.

“It’s a marvel of the world because it’s unique,” Nazim said. “We don’t know who did it, when and why. There’s no single mention of these 32 galleries in the records of the city.”



What are Lyon’s Fishbones?

The Fishbones of Lyon are an underground tunnel network made up of 32 parallel galleries, or passageways, that are built into the hill of Croix-Rousse.

“We call it the fishbones, but if you look at it in a three-dimensional plan, you can see that what we call fishbones are the arms of giant crosses that are dug into the hill,” Nazim said.

They’re built of a stone that can only be found 50-80 kilometers north of Lyon. They’re also large, about 2 meters wide and 2.5 meters high, making them bigger than most underground galleries around the world.

a map of the fishbones tunnel network in lyon

The Fishbones network is made up of 32 parallel galleries, begging the question of why someone would bother digging them. © Walid Nazim

“I’m tall,” said Nazim. “When I walk in a gallery, often I have to bend down because it’s small and really narrow too. But here, these galleries, they were made to pass something other than humans and probably to store something into it. The question is what.

Lyon’s better-known underground tunnels were first discovered in the 30s, when a part of the Fourvière hill collapsed and revealed the network underneath. The Fishbones, meanwhile, remained undiscovered until February of 1959, or according to the official story, 1963.

“In 1963 a building collapsed, and the city had no other choice than to say, ‘There is an underground here. It’s called the Fishbones, and it’s nothing important. We’re taking care of it,’” said Nazim. “And then it’s just silence.”

For the next roughly 40 years, the city maintained its radio silence on the matter, determined not to mess with this most mysterious of Lyon’s treasures. The Fishbones faded into forgotten Lyonnais folklore.

Walid Nazim: A Lyon Fishbones Expert

Nazim is one of Lyon’s resident explorers, walking the city streets looking for undiscovered treasures.

“Since my childhood I’m exploring Lyon. I love this place and I wander everywhere,” he said.

It didn’t take long for him to find the underground tunnels, and he and a team of friends soon began to draw maps and document them. But one particular set of tunnels stuck in his mind.

“I heard about the Fishbones because there was a rumor, maybe 10 years ago. Most people were like, ‘Oh, that’s a legend. Some people say that there are fishbones under Lyon but that doesn’t exist,’” he said.

Aware that it is forbidden to enter the Fishbones, Nazim began to explore under the cover of night.

“That’s what I’m doing one night like that, and I arrive in a beautiful, magnificent place which just hit me to the core, and I’m like woah, I’ve never seen things like that except maybe in Egypt.”

From there Nazim went on a hunt to find out more, looking for books or records that could tell him where the tunnels came from and why.

“I’m like, I have to find a book that tells me the story of that place, and no book. So I’m like I’m going to find the records of the city that talk about it, and no records,” he said.



Fighting against the city

There’s no question that the Fishbones have a long and storied past, sitting under the apartments on the slopes of Croix-Rousse for longer than any current inhabitant’s memory goes back.

But as of the early 2000s when Nazim first started digging into the history of the network, no archeological studies had been done. The city’s silence prevailed, and the tunnels remained unexplored and unpreserved.

“There were no records of the tunnels so I studied the land through the times,” said Nazim.

It was in doing this that he unearthed files from 10 years of underground work that put city workers right in the heart of the Fishbones. In the files: the discovery of 5 cubic meters of human bones in one of the galleries.

“I was like, that’s great, because these bones have maybe been carbon dated, or something like that,” said Nazim. “When I arrived to the city with this report, they told me there were never bones in the Fishbones. ‘Where did you find this document? Who gave it to you?’”

gallery that once contained human bones in the fishbones of lyon

This gallery once contained large amounts of human bones. They disappeared without a trace and are unrecovered to this day. © Walid Nazim

It wasn’t until two years later, in 2009, that the first archeological study of the Fishbones took place, following a petition from Nazim and other Fishbones supporters to stop the digging of the pedestrian half of the Croix-Rousse tunnel, which would cut right through five of the Fishbone galleries.

“This archeological study dates the Fishbones from the 16th century, the Renaissance, and says it’s really not historically interesting so we can destroy part of it to make a tunnel,” said Nazim.

The second half of the tunnel was built, ruining five of the galleries in the network’s lower column. It also changes the way water flows through the hill, making it more likely that other galleries become flooded or corroded over time.

“In 2013 the archeological service of the city said that was a mistake. It’s not from the 16th century. We just dated it from antiquity,” he said.

Nazim could offer no other example of an archaeological dating which made such a grievous mistake. “It’s so different. That doesn’t happen.

Where do they come from?

But even ancient Roman times can’t explain the Fishbones.

“It’s not from antiquity, it’s not from the 16th century,” said Nazim. “We have so many antique vestiges in Lyon, above ground and below ground. Nothing like the Fishbones.”

Rather, Nazim thinks the Fishbones have a much more interesting past, starting with William de Beaujeu, the last Grand Master of the Knights Templar.

“In the 13th century, the land of Miribel and Croix-Rousse belonged to the Lord of Beaujeu, whose lands went all the way up to the place you found this stone [of the Fishbones],” said Nazim.

a dead end gallery in the fishbones of lyon

All of the galleries are dead ends like this one, leading Nazim to believe they were meant to store something. © Walid Nazim

Meanwhile, the only record of parallel galleries apart from the Fishbones is that of the Templar fortress in Acre, near Jerusalem, where a parallel gallery links the fortress and the old port.

“What’s the point to build parallel galleries when you know the money and the power it costs to build a gallery underground?” Nazim said. “I looked where you can find parallel galleries, and the only place I found is Acre in the Templar tunnel.”

Nazim thinks the Fishbones in Lyon acted as a safe for the Templar treasure, as William de Beaujeu evacuated Templar holdings through the secret port tunnel in Acre and across the sea to the Sarrasinières and the Fishbones.

“This is the only theory that can explain all the different parts of the enigma,” he said. “Where the stone comes from, why it goes all the way to Miribel, why we don’t have a single record of the place in the archives.”



The future of the Fishbones

Today the Fishbones are in danger of falling into ruin due to the city’s continued neglect. While he works on a second book about the mystery, Nazim is dedicated to getting the network open to the public.

“A place like that, anywhere in the world it would be open to the public for sure or at least studied,” he said.

Lacking a restoration protocol, archeological studies, and proper protections against future roadworks, Nazim fears the galleries will slowly fall into ruin and be filled with concrete. Meanwhile, the Saint-Bernard church that offers access to the network is in just as bad of shape, desacralized, forbidden to the public, and in danger of being turned into a business center.

As for the city, officials don’t see the Fishbones or the church being open to the public anytime soon, or possibly ever.

“We don’t plan to open the Fishbones to the public for safety reasons. There are many ladders, deep, 20-meter wells. But we’re thinking about a possible virtual visit in 3D,” Lyon Deputy Mayor Jean-Dominique Durand told This is Lyon.

a flooded gallery in the fishbones tunnels in lyon

The Croix-Rousse automobile and pedestrian tunnel changed the way water flowed through the hill, leading some of the galleries to flood. Nazim worries they will soon all be destroyed. © Walid Nazim

Nazim has been pushing the issue for 15 years now and sees another long 15 years ahead of him fighting the city’s position. He hopes that one day tourists and locals alike will be able to access the Fishbones from the Saint-Bernard church and descend into the secret of the city people walk above every day.

“It goes to what was in the Fishbones, why do we have this place here, and what about all these occult societies that grew in Lyon through centuries to spread worldwide,” he said. “This really is something that connects people to their traditions.”

From Acre to Miribel to the Scottish Templar descendants who later settled on the same land, the Fishbones tell a story of Lyon’s power across the world that Nazim believes everyone should know.

“Everyone is concerned by this place,” he said. “Lyon was the crossroads of Europe from the medieval ages to the renaissance all the way to the 19th century. It’s something that is much bigger than Lyon.”


Nazim offers guided tours of the area above the Fishbones, in English and in French.
Email to schedule.

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