The Terrils Jumeaux: The Twin Conical Hills in Lens, France

One of the few things that northern France lacks are tall mountains. However, that does not mean there aren’t any options to climb to higher elevations to enjoy some overlooking views of surroundings.

Enter the Terrils Jumeaux #74 or the Terrils des Loos en Gohelle, the black conical twin hills near the French city of Lens.

These twin conical hills are just two of 51 slag heaps that were artificially made during the coal mining times in this region. Belgium and Northern France, especially the Nord-Pas-de-Calais departments, were known historically for its coal mines. The devastation of the coal mining industry left these hills standing on otherwise flat plains of the region, and are now fueling green tourism.

In this blog post, I will investigate this piece of history and determine if they are worth visiting for especially that they are considered to be part of the UNESCO World Heritage site, the Nord-Pas-de-Calais Coal Mining Basin.

How to get to the Terrils Jumeaux in Lens?

The Terrils Jumeaux in Lens are located about 45 minutes from Lille by TER regional train.

After arriving in Lens, I hopped on a bus #19 headed to the direction of Angres – Duguay-Trouin at the bus station located just outside of Len’s train station. After about 20 minutes, I alighted at a bus stop called Cites des Provinces.

The bus stop Cites des Provinces stands near the entrance of the Base 11/19 historical landmark, a coal mining extraction plant which has retained most of its its facilities, and itself a UNESCO World Heritage site!

To get to the Terrils Jumeaux in Lens, take the bus #19 and alight at the Cite des Provinces bus stop near the Base 11/19 historical site.

The entrance of Base 11/19 coal extraction site in Lens, France is itself a UNESCO World Heritage site.

Hiking to and climbing on the Terrils Jumeaux in Lens

Of course, I went to the Terrils Jumeaux in Lens on a sunny day in Spring as I wanted to make sure that I will enjoy my time there.

After entering the Base 11/19 gate, I took a glimpse of the fascinating coal extraction site surroundings which features old buildings and facilities used to extract coal. There are also some signs around with explanation of the site’s history to help you appreciate the place.

Snapshots from the outside of the Base 11/19 coal extraction site.

I believe there is a lot more to see compared to what I have seen from the outside so I will update this post once I have another trip to specifically check this place in the future.

The Base 11/19 coal mine extraction site in Lens, France.

Walking just a few metres past the Base 11/19 buildings revealed the views of the Terrils Jumeaux #74 conical twin hills.

View of the Terrils Jumeaux #74 twin hills from Base 11/19 coal extraction site.

The trail to the Terrils Jumeaux also starts here and is well-labelled.

No chance of losing your way to the Terrils Jumeaux in Lens.

The trail to the Terrils Jumeaux in Lens. It’s an exciting view to see as you walk towards the twin conical slag heaps.

The slopes of the slag heaps are known to be unfavourable to plants, that is why these conical hills look bald from the distance and they contrast the surroundings that are full of trees.

The horizon slowly appeared as I climbed on the slag heaps. The slag heaps are known to be inhospitable to plants, but nature always finds a way to grow some vegetations even in unfavourable environments.

Further up the trail, I arrived at a plateau. This place offered a 360-degrees view of the surrounding fields and villages. At this point, the short climb and hike already felt very rewarding.

The stairs and slopes before arriving to the plateau.

A picturesque view from the plateau at the Terrils Jumeaux in Lens, France.

The two conical hills of the Terrils Jumeaux in Lens as viewed from the plateau.

I felt ecstatic upon reaching the chateau so I brought up my phone and vlogged to show the surroundings, and what I thought is the crater where the coal was mined.

Looking visibly happy upon seeing the fabulous views from the plateau at Terrils Jumeaux in Lens.

As I continued my hike and searched for the trail to the first conical hill, which was fenced, I bumped into a signage saying that the hill is inaccessible for climbing. This was a bummer as I would have loved to climb on both slag heaps!

The supposed entrance to climb the first conical hill… but what is that sign?

I wanted to climb on both hills but one of them is sealed off with a fence, unfortunately.

As I turned my sight to the next hill, I saw a group of people climbing on its slopes and figured I need to go there and follow them

Local hikers climb on the slag heap with their dogs for leisure and exercise.

Highlights of the Terrils Jumeaux in Lens, France.

The climb on the second hill cone of Terrils Jumeaux in Lens begins!

View of the first conical hill from the halfway trail of the second one. You will notice the Base 11/19 extraction site on the lower right of the photo.

Halfway through the hill and just about my summit assault, I stumbled into what I think is a problem that made the climb a bit more risky: the texture of the slope is loose and slippery with regular shoes!

So my advice to you if you’re going to climb on any slag heap or terrils in Northern France is to wear a pair of proper hiking shoes or trail running shoes with spikes or grips. They will make a huge difference in terms of safety and fun!

Fortunately, my brain kicked in and I found a strategy to conquer the hill’s summit. I used the two ditches to climb the way up and succeeded!

Achievement unlocked! My first summit to the peak of a slag heap in Northern France.

The peaks of terrils or slag heaps offer fascinating panoramic views of the surrounding areas. Trail runners are often use these hills for their training sessions.

Other slag heaps and hills in the distance are visible. I wondered if I should conquer and climb on all of them. 🤔

After climbing to the top of Len’s Terrils Jumeaux, I started a leisurely descent with rewarding panoramic views. I vowed to wear proper hiking shoes or better yet, a pair of trail running shoes and train here.

Having spent a great day trip to Len’s Terrils Jumeaux, I returned to Lille highly satisfied and with a note in mind that there are (still) many other terrils to explore in Northern France. How exciting!

Here’s a final video clip showing the highlights of this trip to remember: