In the distance, the Alps glow—but we are traveling through the Jura, a lesser-known mountain range that separates northwest Switzerland from France. The Jura are lower and gentler than the Alps and mostly covered in forests. Their rocks are also older than those in the Alps, holding ancient secrets buried deep within their limestone formations.

Fritjof Hilgenfeldt (a photographer and a friend) and I begin our journey from Grenchen in total darkness. At 6 a.m., only our bike dynamos lead us through the Bettlachstock-Hasenmatt forest reserve, an ancient and extensive beech woodland named a UNESCO World Heritage Site in 2021.

Finding dinosaur tracks

Scattered near the small village of Lommiswil are a series of large holes in the rock face. At first, they seem to be the result of excavation tools or erosion. However, experts have uncovered a different story. The depressions in the cliff are footprints left behind more than 150 million years ago by 100-foot-long giants that roamed the Earth. These are Lommiswil’s dinosaur traces.

The traces were discovered in 1987 during an excavation at the local quarry. Approximately 450 footprints were found, some as large as one-and-a-half meters in diameter. Due to their size and patterns, experts believe they were left on the ground by a sauropod, a long-necked herbivore that was approximately 80-100 feet long, weighing the equivalent of six elephants.

“We cannot be totally sure which species made a footprint. But we can make very informed judgments,” says Stephen Brusatte, paleontologist at the University of Edinburgh and scientific advisor to the Jurassic World franchise. “We act like the prince in Cinderella: instead of a glass slipper, we try to match the footprints to the feet of dinosaur skeletons. Sometimes this is straightforward. If you find a bunch of bathtub-sized impressions, you know it’s going to be a sauropod.”

(How to bring a 75-foot-long dinosaur back to life)

It’s hard to imagine now, but the Jura forests we ride through today used to be shallow coastal lagoons, tidal flats, and muddy areas—the perfect ground for the magic of fossilization to take place.

“An animal walks on sand or mud and makes some footprints,” explains Brusatte. “If those are baked in the sun and hardened, and then covered and sealed, then those footprints could petrify into solid rock and turn into fossils. I can’t fathom the odds of a single footprint becoming a fossil, but it must be millions to one.”

Over millions of years (the dinosaurs ruled Earth for 150 million years), and billions of animals walking around and leaving footprints, the miracle sometimes happens. But it then takes even more time, tectonic forces, erosion, and luck to lift what was once a seashore into the rock face we see today.

Lommiswil proved to be a groundbreaking discovery for the region. Subsequent finds revealed a connection between the tracks as part of a larger megatracksite called the “dinosaur freeway.” Since many sites are not near a road, we set out to visit as many as possible on a gravel bike and connect them as if the same giant had left them. 

The second set of footprints

From Lommiswil, we start climbing the Hasenmatt. The road steadily ascends from 1,575 feet to 4,741 feet. It’s a long and beautiful climb, entirely on gravel, always shaded by a deep forest of beeches, firs, and spruce. After more than an hour, we reach the top of the pass and enter the Canton Jura. We soak up the warm sun at the Bergrestaurant Althüsli before heading down through the dark and cold north face of the mountain.

In Moutier, we spot the second set of footprints. Just over a mile outside the center, carved out of another mountain slope, are Moutier’s dinosaur tracks—discovered in 2017 while excavating another local quarry.

Around 25 footprints have been found here, and research confirms, once again, that they belonged to a sauropod that lived about 150 million years ago.

Dinosaur museums and sites

From Moutiers, we climb another three miles before descending into a beautiful, remote area toward the village of Courfaivre. After four hours in the saddle, it’s time for a break at the Jubin Confiseur bakery, where we discover the petits pains en banderilles, a series of mini bread rolls held together by a long skewer that we nickname “bread kebab.” We also refuel with double espressos and cappuccinos at Bar 19 L’Hôtâ, where the many photos of cyclists hanging on the bar walls shine as a good omen.

The midpoint of our ride is Porrentruy. Here, we reencounter our sauropod. Just outside the city center, we stop at the Jurassica Dinotec, where over a hundred tracks were uncovered in 2007 during the renovation of the education center. Today, the footprints of sauropods and theropod (likely Allosaurus) are on display in the courtyard of the facility and protected by large glass panels.

The Dinotec is a satellite branch of the Jurassica Museum in Porrentruy, the town’s natural history museum. Unfortunately, the museum is currently closed for renovations until 2027. However, the museum’s botanical garden remains open and is worth a visit.

Before continuing our adventure, we fuel up with a cordon bleu—a Swiss steak filled with cheese and ham, then breaded and fried—at the Restaurant de la Croix Fédérale.

Soon after we leave Porrentruy, we find ourselves on very steep single tracks, where we must push our bikes uphill for half an hour. On the way home, we see signs for the Prehisto Parc in Réclère, a forest trail featuring 45 life-size dinosaur replicas hidden among the trees. I decided to postpone this visit for another day; my 4-year-old would be upset if I went without her.

The road home

The final tracks of the day are the dinosaur tracks in La Heutte, discovered between 1992 and 1996. The footprints are located right beside the trail and were attributed to sauropods and theropods that lived during the late Jurassic period. In total, approximately 14,000 footprints are estimated to be present across the wider Jura carbonate platform. This area includes more sites than the ones we visited today, and not only from the Jurassic period.

At around 8 p.m., 14 hours after we started, we turn our bike lights back on. There’s only one climb left, but it’s eight miles long, and we cycle the last two in the pitch dark—so dark that Fritjof is hit by a bat. When we stop, we’re both exhausted but still buzzing from the excitement of seeing ancient dinosaur fossils.