Best natural monuments around Cayeux-Sur-Mer offer a diverse landscape characterized by unique geological features, rich wildlife, and expansive scenic views. Situated on the southern edge of the ecologically significant Baie de Somme, the area features vast natural habitats including dunes, marshes, and pebble beaches. Visitors can explore dramatic chalk cliffs, important ornithological reserves, and extensive coastal paths. This region provides opportunities to observe diverse flora and fauna within its wild coastal setting.
Last updated: May 24, 2026
Highlight • Natural Monument
Translated by Google •
Tip by
Highlight • Beach
Tip by
Sign up now to discover places like this
Get recommendations on the best single tracks, peaks, & plenty of other exciting outdoor places.
Sign up for free
Highlight • Natural Monument
Translated by Google •
Tip by
Highlight • Forest
Translated by Google •
Tip by
Highlight • Natural Monument
Translated by Google •
Tip by
Sign up for free to discover even more natural monuments around Cayeux-Sur-Mer.
Sign up for free
Already have an account?
Start today with a free account
Your next adventure awaits.
Login or Signup
The cliffs are made of chalk and are impressive to look at.
3
0
Here in Ault begin the chalk cliffs, which stretch all the way to Normandy and repeatedly appear as enormous cliffs.
4
0
The cliffs around the beach of Ault are composed of chalk from the Upper Cretaceous, more precisely from the Turonian and Coniacian (around 83 million years ago to 90 million years ago). They are strewn with flint nodules which highlight the subhorizontal stratification planes (the formation of flint has already been discussed in Discovery of the geology of the cliffs of Étretat, presentation of an excursion from the beach of Tilleul (Antifer) to the Porte d'Amont (Étretat Nord)). The relative proportion of chalk and flint is around 90-95% chalk to 5-10% flint. Flint horizons are stratigraphic markers. On the cliffs of Ault, the regular flint band called Seven Sisters is recognizable and characterizes the boundary between the Middle Coniacian and the Upper Coniacian (around 87 million years ago). The boundary between the lower and middle Coniacian is marked by the Shoreham 2 marl level, which is more difficult to identify. These lithostratigraphic markings allow in particular the correlation of distant deposits, such as between the Normandy and Picardy coasts, or between the French and English coasts.
3
0
A green setting in the heart of the cliffs, classified as a picturesque area since 1959. The Bois de Cise is an exceptional natural area, a small natural forest, originally wild and abandoned, which became a famous seaside resort during the Belle Époque under the leadership of a visionary who stopped at nothing. This coastal forest was originally a wild forest and a hunting ground in the Middle Ages. At the end of the 19th century, the Bois de Cise was sold off in lots on the initiative of a property developer and became a famous seaside resort of the Belle Époque. Today, it is a charming holiday and walking area that is best explored on foot via the narrow paths and wooden steps that crisscross the area. Very beautiful villas bear witness to the prosperous years before the First World War. Don't forget to go to the panorama, like Victor Hugo in his time, a fantastic viewpoint from which you can see the mouth of the Bay of Somme.
0
0
The cliffs around the beach of Ault are composed of chalk from the Upper Cretaceous, more precisely from the Turonian and Coniacian (around 83 million years ago to 90 million years ago). They are strewn with flint nodules which highlight the subhorizontal stratification planes (the formation of flint has already been discussed in Discovery of the geology of the cliffs of Étretat, presentation of an excursion from the beach of Tilleul (Antifer) to the Porte d'Amont (Étretat Nord)). The relative proportion of chalk and flint is around 90-95% chalk to 5-10% flint. Flint horizons are stratigraphic markers. On the cliffs of Ault, the regular flint band called Seven Sisters is recognizable and characterizes the boundary between the Middle Coniacian and the Upper Coniacian (around 87 million years ago). The boundary between the lower and middle Coniacian is marked by the Shoreham 2 marl level, which is more difficult to identify. These lithostratigraphic markings allow in particular the correlation of distant deposits, such as between the Normandy and Picardy coasts, or between the French and English coasts.
2
0
The cliffs around the beach of Ault are composed of chalk from the Upper Cretaceous, more precisely from the Turonian and Coniacian (around 83 million years ago to 90 million years ago). They are strewn with flint nodules which highlight the subhorizontal stratification planes (the formation of flint has already been discussed in Discovery of the geology of the cliffs of Étretat, presentation of an excursion from the beach of Tilleul (Antifer) to the Porte d'Amont (Étretat Nord)). The relative proportion of chalk and flint is around 90-95% chalk to 5-10% flint. Flint horizons are stratigraphic markers. On the cliffs of Ault, the regular flint band called Seven Sisters is recognizable and characterizes the boundary between the Middle Coniacian and the Upper Coniacian (around 87 million years ago). The boundary between the lower and middle Coniacian is marked by the Shoreham 2 marl level, which is more difficult to identify. These lithostratigraphic markings allow in particular the correlation of distant deposits, such as between the Normandy and Picardy coasts, or between the French and English coasts.
3
0
Visitors frequently appreciate the dramatic chalk cliffs and expansive bay areas. Highly rated spots include La Cise Cliff, known for its stunning white chalk cliffs, and the Ault Chalk Cliffs, which mark the beginning of the Normandy cliffs. Cape Hornu also offers panoramic views of the Bay of Somme and its wildlife.
The region is characterized by its unique geological features. You'll find extensive pebble beaches, particularly in Cayeux-sur-Mer itself, where the 'blue pebbles' are renowned for their purity. The dramatic white chalk cliffs, such as those at La Cise Cliff and Ault Chalk Cliffs, are composed of chalk from the Upper Cretaceous period, often strewn with flint nodules. The vast Baie de Somme also features diverse landscapes including dunes, marshes, and grassy plateaus.
Absolutely. The Baie de Somme is a major migratory route for thousands of birds and home to France's largest colony of common seals. Pointe du Hourdel is a prime location for seal watching, with both grey and harbour seals often seen on sandbanks at low tide. The Hâble d'Ault Nature Reserve, a former lagoon, is an important ornithological reserve sheltering nearly 270 species of migratory birds.
The area offers a variety of outdoor activities. You can enjoy long walks along the extensive pebble beaches and coastal paths. Hiking is very popular, with routes like the 'Le Hourdel Loop' or 'Observatory 4 – Hable d'Ault Observatory loop' available. For cycling enthusiasts, there are numerous routes for MTB and gravel biking, such as the 'Lighthouse far away from the beach – Saint Valery sur Somme loop' or 'The Hâble d'Ault Route'. You can find more details on these activities in the Hiking around Cayeux-Sur-Mer and MTB Trails around Cayeux-Sur-Mer guides.
Yes, several natural monuments are suitable for families. The Baie de Somme offers opportunities for gentle walks and birdwatching, which can be engaging for children. Cape Hornu is also listed as family-friendly, providing scenic views and a path along the coast. The extensive Cayeux-sur-Mer beach is great for long walks and beachcombing, especially at low tide when sandy expanses appear.
The natural monuments can be enjoyed year-round, but each season offers a different experience. Spring and autumn are ideal for birdwatching, especially in the Baie de Somme and Hâble d'Ault Nature Reserve, due to migratory patterns. Summer provides pleasant weather for beach activities and longer walks. Even winter visits can be rewarding for observing the raw natural beauty and dramatic coastal landscapes, often with fewer crowds.
Yes, the region offers many easy walks. The general terrain around Cayeux-sur-Mer, including the dunes, marshes, and grassy plateaus, is gentle and suitable for various fitness levels. The 'Observatory 4 – Hable d'Ault Observatory loop from Cayeux-sur-Mer' is an example of an easy hiking route. The long boardwalk along Cayeux-sur-Mer beach also provides a flat, accessible path for a leisurely stroll.
Many natural areas and walking paths around Cayeux-sur-Mer are dog-friendly, but it's always best to check specific regulations for nature reserves or protected areas. Generally, dogs on a leash are welcome on coastal paths and beaches, especially during off-peak seasons. Always ensure to clean up after your pet.
Given the coastal and often windswept environment, it's advisable to dress in layers. Comfortable walking shoes are essential, especially for exploring trails and pebble beaches (water shoes are recommended for the pebbly beach itself). A windproof and waterproof jacket is highly recommended, regardless of the season, as weather can change quickly. Don't forget sun protection, even on cloudy days.
While primarily natural, some sites have historical significance. Cape Hornu, for instance, is near Saint-Valery-sur-Somme, a town with a rich medieval history. The cape itself has historical ties to William the Conqueror and Joan of Arc. The Chapelle des Marins, dedicated to sailors, is also located along the coastal path near Cap Hornu, adding a cultural layer to the natural beauty.
For additional details about Cayeux-sur-Mer and the Pointe du Hourdel, including local attractions and practical information, you can visit the official tourism website: somme-tourisme.com.
The Cayeux-sur-Mer beach is unique due to its extensive stretch of pebbles and shingle, which gives way to vast sandy expanses at low tide. These 'blue pebbles' are a natural marvel, originating from the erosion of chalk and flint cliffs in Normandy and shaped by oceanic currents. The beach is also home to Europe's longest boardwalk, lined with over 400 colorful beach cabins, adding to its distinctive charm.


Extend your search for the best caves by checking out these guides of the top ones around Cayeux-Sur-Mer: