Viroinval ft. Nismes & Fondry des Chiens hiking trail

April 2021. As COVID-19 still rages and we still live under coronavirus countermeasures, Oriol and I were looking fore hiking trails. As a long-time follower of Denzil‘s Discovering Belgium, I looked for inspiration on his hiking and nature blog and settled for ‘A 23 km hike around Viroinval‘.

After stopping by the Geographic Centre of the European Union of the 15 on the N990 Rue Roger Delizée for photos, a pee and a waffle, we drove to Nismes to park the car and start the 23 km hike. It was a Tuesday, so there wasn’t a Saturday market blocking us. 


It wasn’t my first time in Nismes. I went there as a child as a school outing. I was 10 years old I think. Our headmaster was an avid rock climber and I think he wanted to promote the sport. 

The second time I got acquainted with Nismes was with De Rode Ridder. This Red Night is a comics series centered around Johan, the Red Night. In album 135 ‘De Slangengod‘ (‘The Snake God‘), the nearby Fondry des Chiens is evil magician Magor‘s lair. 

Anyway. Nismes is beautiful. It has the same vibe as Bayeux (yes, from the tapestry) in Normandy. Definitely quaint, still lively, a medieval look, manors, a water mill, a castle. 


Fast forward to 2021. 

Since 1977 the area is called Viroinval. Viroinval is a municipality located in in the province of Namur in the region of Wallonia, in Belgium. On January 1, 2006 Viroinval had a total population of 5,680. The total area is 120.90 km² which gives a population density of 47 inhabitants per km².

The name Viroinval, Valley of the river Viroin, was chosen for the municipality that was formed by fusing eight villages: Dourbes, Mazée, Le Mesnil, Nismes, Oignies-en-Thiérache, Olloy-sur-Viroin, Treignes, Vierves-sur-Viroin.

Fondry des Chiens

Fondry des Chiens.

The hike’s and the area’s main attraction is the Fondry des Chiens. The Fondry des Chiens is a sinkhole in the Viroin-Hermeton Nature Park. It is a large ravine-like well with jagged protruding rocks formed by washed away limestone from which ferrous, washed-in mineral was mined for centuries.

The Fondry des Chiens is a doline or gouffre of 100 meters long and up to 20 meters deep. These canyons only occur in Belgium in the Viroin region. Fondry des Chiens and Le Matricolo are the largest canyons in the area.

The creation of the Fondry was hypothesized to be the result of the action of acid rains on the limestone layers deposited about 400 million years ago by the warm seas, which then covered the land, leaving behind calcareous coral reefs. The seas of the first era also left an iron-containing sand layer on top of the limestone layers.

After retreating from the sea, the water from tropical rains, acidified with carbon dioxide from decayed vegetation, seeped in and affected the subsoil of limestone rocks. This caused depressions in the underlying limestone layer. Large amounts of water washed out vertical pipes and horizontal corridors at weak spots in the limestone cliffs. Those cavities could also collapse, leaving large boulders on the bottom. The iron in the covering sands was washed away by the ingress of rainwater and deposited at the bottom of the depressions and cavities and combined with the lime.

About two million years ago, during the Pleistocene, climatic conditions changed and the overlying sand layers were washed away and the underlying limestone layer came to the surface. 

Only in the flushed vertical cavities did the ferrous sands remain. In the Fondry des Chiens, the presence of iron is still visible in the red color of the rock.

From the Iron Age to the nineteenth century, the iron ore was mined and processed in the Fondry des Chiens. Over time the hole was deepened further and limestone cliffs remained.

It is this human activity that gave rise to part of the name, coming from the French fonderie (smelter). 

If we can believe, the etymology is Foundry of Infidel Dogs. Muslim warriors are said to have called the locals infidel dogs. 

The hike

I’m quite allergic to double work so I gladly refer to Denzil’s blog post on the hike for directions and descriptions

Sometimes finding the right path is a bit hard. Denzil’s itinerary combines local trails with Grandes Randonnées (GR), recognizable by their flag of Poland styled signs. 

Often we found or the red and white crossed as an X to mark this is not the right way, choose the other option. Sometimes we found the logo adapted to mark you need to take a turn left or right.

Not this way.

 My Apple Watch and iPhone Health App counted 25 km instead of 23. The hike is varied. Forrest path, grass, elevation, tarmac… In total, I climbed 452 metres. Some parts require some dexterity to go up or down. Albeit long, the hike is not a climb. Jost bring decent hiking shoes with grip and don’t wear denim to avoid chafing.

We enjoyed our day in a setting unfamiliar to us city pigeons. 

Next time: Chemin de fer à vapeur des 3 vallées (Mariembourg-Treignes)

Viroinval is is also home of the Chemin de fer à vapeur des 3 vallées (Mariembourg-Treignes) or CFV3V. The Three Valleys Steam Railway is a heritage railway created in 1973.

It is a non-profit society that operates a railway from the town of Mariembourg, near Couvin, to Treignes

The length of the railway runs about 14 km over standard gauge track. The society’s name comes from the three rivers followed by the line. Eau Blanche, Eau Noire, and the Viroin. The heritage railway connects with the greater Belgian rail network in Mariembourg.

The society runs two main facilities. The society has constructed its own platforms near the old locomotive roundhouse and water tower in Mariembourg, and in Treignes, a former border station, a museum with a large workshop has been built. The last 3 kilometers from the line (partially established in France) are no longer usable, as its tunnel has been sold and turned in a mushroom growing plant.

Founded by former rail employees, the society purchased many steam engines from the largely nascent coal industry in its early years. Since then, it has also acquired representative rolling stocks from Belgium, France and Luxembourg, and from countries where steam locomotives were still in use, such as Poland and East Germany.  


11 Comments Add yours

  1. Denzil says:

    Super account Timothy! And lovely photos. It has inspired me to revisit the area!

    Liked by 2 people

    1. Timothy says:

      Thank you! It’s a hike which must be beautiful in every season.

      Liked by 2 people

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s