It was around five in the morning on the shores of Lake Prespa in Northern Greece when I first encountered Ridha Dhib: a figure moving slowly along the water’s edge, a walking stick in hand, conversing with a strange, synthetic voice coming from a small red speaker clipped to his hip. The lake was still, the light turning pink. I hadn’t been able to sleep. I was hoping to see a pelican or maybe a bear. I stood watching this mysterious man a long time. I thought to introduce myself, but I didn’t want to interrupt him.

He was, I would later learn, a French-Tunisian walking artist — he prefers the term martiste, from the French marche-artiste — who had trained at the École des Beaux-Arts in Toulon before his obsession with the line took him, gradually and then entirely, out of the studio and onto the road. For some years he has been making long-distance walking performances: a pilgrimage to Compostela, a walk to Sousse, his hometown in Tunisia, and more recently Ex-Tracés, a journey of 5,232 kilometres from Paris to Mardin, near the Turkish-Syrian border. That walk had brought him to Prespa, where he was performing a work it had inspired. Soon he would be on his way to Nafplio in southern Greece, where he would repeat that performance, though he had learned he would only have ten minutes due to time constraints.

It was this constraint that became the germ of an entirely new work. How do you present a long-duration walk to a time-poor audience? What do you keep? What falls away?

Henri Matisse once suggested that a square metre of blue is bluer than a square centimetre of blue. It is a deceptively simple observation: that quantity does not merely increase, at some undefined threshold, its quality transforms.

It’s an idea Dhib will explore in Mnémosyne, his upcoming 100-day walk from Paris to Nafplio. The work will unfold across thousands of kilometres, through changing landscapes, weather systems, encounters and physical states. Yet at the end of the journey, all of this accumulated experience will be transformed into a final artwork lasting just ten minutes.

I did the maths. Mnémosyne condenses around one thousand hours of walking (about ten hours a day for 100 days) into ten minutes, a ratio of roughly 6,000 to 1. Every second of the final performance would contain hours of walking, footsteps, fatigue, conversations, weather, heartbeats, thoughts.

But when I described this as a dramatic compression, Dhib corrects me.

“For me, it isn’t compression,” he says. “It’s distillation.”

He compares the work to the distillation of countless Damask rose petals into a few precious drops of essence – something he watched his grandmother do in Tunisia as a child. The flower disappears. The fragrance is what remains. Compression makes something smaller. Distillation asks a different question: what is essential?

“For me, it isn’t compression… It’s distillation.”

Following the line

Although Dhib is now known for long-distance walking performances, his practice did not begin with walking.

“I come from painting and drawing,” he explains. “And actually my obsession was always the line.”

At first, the line existed on paper. Then it escaped the frame. It moved into installation, into space, into landscape. Eventually the GPS trace became another form of drawing, not made by the hand, but by the whole body.

“The body becomes a brush on the skin of the Earth.”

Walking was not a decision, he says. He did not wake up one day and decide to become a walking artist.

“I followed the line. The line took me outside.”

For Dhib, the walking body does not simply travel through a landscape. It creates a relationship with it. The path is not a passive surface beneath the feet. It acts upon the walker. This is why time matters. A one-day walk, a ten-day walk and a month-long walk are not simply different quantities of the same experience. Like Matisse’s blue, at a certain scale the nature of the experience itself begins to change.

“After a month of walking,” Dhib says, “you become a true inhabitant of the path. The path welcomes you.”

The vital cost of the path

In his novel Slowness, Milan Kundera identifies something that walking artists understand intuitively. When we delegate the faculty of speed to a machine, Kundera writes, our body is outside the process, speed becomes noncorporeal, pure, ecstatic, and the body disappears from its own journey. Walking refuses this. It insists that distance must be paid for, not financially, but physically.

“You pay with your body,” Dhib says. “You pay with sweat. You pay with fatigue.”

He calls this the “vital cost” of walking. For Mnémosyne, Dhib abandons the kilometre as the unit of measurement and replaces it with the heartbeat. The journey is no longer measured by distance travelled but by the vital cost the path demands from the body. There is a secret bond, Kundera also writes, between slowness and memory. Perhaps the vital cost is also what makes the journey memorable, because the body is never outside the process. Every kilometre is felt.

And others recognise something in that. During a previous performance, walking from Paris towards Tunisia, Dhib remembers arriving in Italian villages where people asked where he had come from.

“Paris,” he would reply.

“Viene da Parigi!” they would exclaim.

Not simply because of the distance, he believes, but because they understood something older: the figure of the pilgrim, the person who has crossed the world through effort, exposure and vulnerability. The journey has been paid for, and that counts.

What remains?

One of Dhib’s most important encounters happened during Ex-Tracés, after around 2,000 kilometres on the road. It was almost unremarkable. A Croatian farmer was working in a field. Dhib was walking along the road. The two men saw each other from a distance and raised their hands in greeting. They did not speak. They did not meet. A ploughed field separated them. But something passed between them.

“In that instant I thought, just for that greeting, that encounter – it was worth walking 2,000 kilometres.”

This tiny moment became part of the thinking behind Mnémosyne. Because what remains from a journey is not always what we expect. The mind does not archive experience logically. It does not give every moment equal weight or significance. Some objectively important moments disappear. Other almost invisible moments return years later.

“Some things that mark us at the time do not remain,” he says. “And something that affected us almost imperceptibly can reappear much later.”

Perhaps there is a mercy in this forgetting, the way the mind lets the landscape blur so that only the essential weight of the journey remains. We lose the details in order to keep the feeling.

A memory larger than one mind

This is where artificial intelligence enters Mnémosyne, not as a replacement for human experience, but as another participant in the work. Each day of the walk, Dhib will create what he calls a cardiocartography: a four-dimensional digital object containing multiple layers of the journey. GPS traces. Heartbeats. Weather. Geology. The position of constellations in the cosmos. The subjective experience of the walker. His reflections will be recorded along the route, creating a daily account of what happened, what was felt, what seemed important. All of this will be given to an AI protocol developed by Dhib.

The purpose is not for the machine to reconstruct the journey, but to search for connections that might otherwise remain invisible.

“It is there to reveal layers of reality that are outside our comprehension,” he says.

There is simply too much information for a human mind to hold at once. The question is not: does the AI know better?

“The AI does not know better than me. It follows and extends my way of seeing, helping bring unexpected correlations to the surface rather than inventing meaning.”

The final ten minutes

At the end of the 100 days, Dhib will give the AI one final task. It will have access to the entire digital memory of the journey – the accumulated traces of body data, landscape, weather, thought and encounter. Then he will ask it one question: “What remains?”

He does not know what form the answer will take. A text. A voice. A song. A poem. Something else entirely.

“If I already knew what would come out,” he says, “there would be no point.”

The artist makes the structure, then steps back. There is a patience to this, and a wonder — perhaps something of the little boy watching his grandmother boil roses. A hundred days distilled into ten minutes. Thousands of steps become a trace. Thousands of petals become a few drops of oil. A square metre of blue becomes something more than blue.

What does a hundred days of walking become? In Nafplio, this November, a little red speaker will tell us.

Ridha Dhib begins Mnémosyne on 29 July in Paris. His walk will culminate on 5 November in a performance at the Department of Performing and Digital Arts, University of the Peloponnese, Nafplio, Greece.