For weeks, a black mountain loomed over the Seine where Paris’ oldest bridge should have been. On Monday evening, its doors finally opened.
Inside, Paris smells different. The air carries the scent of earth after rain - damp ancient stone, cellar walls, perhaps a trace of smoke.
Visitors step from the bright riverfront into a dark passage lined with glowing photographs of caves, as a low electronic pulse seems to breathe through the walls.
Beneath it all, the old cobblestones of the Pont Neuf rise and fall underfoot.
The Pont Neuf Cavern, a monumental installation by French street artist JR - also known as the French Banksy - is free to enter around the clock through June 28.
Made largely from printed fabric and air, it transforms the 17th-century bridge into an artificial cavern rising 18 meters (59 feet) above the Seine.
"It feels like the city has disappeared,” said Léa Martin, a 22-year-old art student from Lyon on Tuesday. "You know the river is right outside, but for a moment you’re somewhere ancient.”
The smell is central to the illusion.
Olfactory expert Sarah Bouasse created two shifting scents: drawing on geosmin and isoborneol, compounds associated with the aroma released when rain strikes dry earth.
It changes along the crossing: first wet earth and mineral dampness, then something warmer, smokier and faintly animal.
"Usually I cross here without looking up once,” said Michel Dupré, a 67-year-old retiree, blinking as he emerged into daylight. "Today I felt the stones under my feet. And smelled them too. It makes you walk like a child again.”
A sound installation by Thomas Bangalter, formerly of the French electronic duo Daft Punk, accompanies the work, filling the cavern with low rumbles, echoes and pulses.
Completed in 1607, the Pont Neuf - despite its name, "New Bridge” - is the oldest bridge still standing in Paris.
JR’s installation asks people to experience the familiar crossing through their noses, ears and feet.
It also pays tribute to Christo and Jeanne-Claude, whose 1985 wrapping of the bridge in pale golden fabric drew an estimated 3 million visitors.
Their work covered the Pont Neuf in light.
JR sends visitors into darkness.
"You enter into the darkness,” he has said, "and emerge into the light on the other side.”
Visitors can also raise their phones to activate an augmented-reality experience developed with tech company Snap.
Digital bats trail light through the cave, passing bodies leave ghostly traces and a dancer materializes in space.
JR has linked the work to Plato’s allegory of the cave, in which prisoners mistake shadows for reality. Today’s cave walls, he argues, are screens and the algorithms that shape what people see. Yet the installation’s strongest effects require no phone.
"It’s completely strange,” said Nadia Benali, 34, smiling beside the artificial cliffs. "Paris needs things that make people stop.”
When the cave closes, its fabric will be reused or recycled.
The mountain will vanish, traffic will return and the Pont Neuf - older than the French Revolution - will emerge into the light once more.
