The seven tunnels of the Belletrud aqueduct starting from Baume Obscure

This is a physically demanding hike, but the wooded areas you will pass through are remarkable. The highlight of the day is the passage through the tunnels bordering the Siagne cliffs. The Deux Goules cave is one of the local attractions.

Details

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  • Walking
    Activity: Walking
  • ↔
    Distance: 16.84 km
  • ◔
    Average duration: 7h 10 
  • ▲
    Difficulty: Difficult

  • ⚐
    Back to start: Yes
  • ↗
    Ascent: + 816 m
  • ↘
    Descent: - 819 m

  • ▲
    Highest point: 957 m
  • ▼
    Lowest point: 455 m

Photos

Description of the walk

From Saint-Vallier-de-Thiey, take the road to Saint-Césaire-sur-Siagne and at the first crossroads, turn right towards the Grotte de Beaume Obscure, where there is a large car park.

(S/E) Below the car park, take the marked recreational route called Circuit Vallon et la Combe, created by the Grotte de Beaume team. Follow it until you reach the sign that says: turn around, continue straight ahead. This sign is actually for people who are only doing the recreational route. You will reach a crossroads with a cairn.

(1) Continue straight ahead on this beautiful, pleasant, flat, wooded path until you reach marker 78.

(2) Be careful here, as there are two marker posts 78 a few metres apart. At thesecond one, turn right and follow the signs for Arche de Ponadieu via the GRF510 marked in white and red. Follow a steep descent to marker post 79.

(3) Stay on theGR® and you will soon find marker 80. Continue straight ahead towards Chapelle Saint-Jean and you will reach Vallon de Bramafan.

(4) Stay on theGR® trail, find marker 82 and then follow the tarmac road to arrive below the Chapelle Saint-Jean road.

(5) Take the path behind the chapel, join and follow the road. Pass a car park and arrive at the Vieux Pont.

(6) Cross the Siagne river on this bridge and continue along the wooded track. The last few metres are very stony. Then continue along a path until you reach marker 84.

(7) Leave theGR® here and turn left towards Rouyère on one of the most beautiful paths in the area, lined with oak trees. At the crossroads at marker 90, keep left and you will reach the ruins of the hamlet of Rouyère, marker 87.

(8) Turn left onto the descending path. After a large right-hand bend, begin an easy climb and finish at a place called Le Cavalet.

(9) Descend until you reach marker 88.

(10) Turn left onto the track and you will soon reach the start of the Belletrud aqueduct trail.

(11) Take this path opposite, but be careful on this section as it is carved into the cliff overlooking the La Pare River, which is about 100 metres below. Follow the blue markings.
There are seven tunnels to pass through. Be careful to keep your head down, as the ceiling height is 1.60 metres maximum. For safety reasons, go through all the tunnels and follow the water pipe.
A few instructions for these tunnels:
- At thethird tunnel, continue straight ahead.
- Thefourth tunnel is 100 metres long.
- the5th is crossed by climbing up on all fours,
- Thesixth tunnel has a slight bend.
After the last tunnel, you will come to a large concrete water collection square.

(12) Go over it, continue east for about 20 metres, two cairns at the same level as the concrete square, and follow the blue markings to the footbridge over the Siagne.

(13) Cross it (it is a metal bridge supporting the water pipe), then climb the two staircases. Continue along the flat path, bordered by a cliff. You will come to a hairpin bend. Leave the track and head left towards a small grassy clearing.

(14) Turn right and, as soon as possible at another clearing very close by, move into the stony bed of the Vallon de la Combe. Follow it, pass two large steps within this bed and continue to a cairn on the left.

(15) Continue and, atthe second cairn, you can climb about ten metres without any danger to see the Deux Goules cave. Please note that the entrance to the cave is equipped with a safety line. Then continue along the dry riverbed. Return to the crossroads at marker 79.

(3) Turn right to retrace your steps. You will reach number 6 on the fun route. Turn left to walk alongside the entrance to the Grotte de Beaume cave. Continue on to return to the car park (S/E).

Waypoints

  1. S/E : km 0 - alt. 612 m - Parking at the Baume Obscure cave
  2. 1 : km 0.73 - alt. 591 m - Trail junction
  3. 2 : km 1.46 - alt. 603 m - Beacon 78
  4. 3 : km 1.59 - alt. 563 m - Marker 79. Crossroads of the circular loop
  5. 4 : km 2.73 - alt. 619 m - Bramafan Valley
  6. 5 : km 3.43 - alt. 590 m - Saint-Jean Chapel
  7. 6 : km 4.01 - alt. 587 m - Old Bridge
  8. 7 : km 5.31 - alt. 721 m - Beacon 84
  9. 8 : km 6.6 - alt. 858 m - Beacon 90 Rouyère
  10. 9 : km 8.38 - alt. 921 m - Le Cavalet
  11. 10 : km 10.23 - alt. 730 m - Beacon 88
  12. 11 : km 10.46 - alt. 722 m - Start of the Belletrud trail
  13. 12 : km 13.21 - alt. 630 m - Concrete block
  14. 13 : km 13.68 - alt. 462 m - Bridge over the Siagne
  15. 14 : km 14.39 - alt. 512 m - Small clearing
  16. 15 : km 14.69 - alt. 523 m - Cairn
  17. S/E : km 16.84 - alt. 615 m - Parking at the Baume Obscure cave

Notes

No water on the route.
After the7th tunnel, the pipe has a small leak that will allow you to cool off a little.
Hiking boots and walking sticks are recommended.
Good physical condition is required.
A headlamp is a plus for travelling through the long tunnel.

Worth a visit

Always be cautious and plan ahead when you're outdoors. Visorando and the author of this route cannot be held responsible for any accidents occurring on this route.

The GR® and PR® markings are the intellectual property of the Fédération Française de Randonnée Pédestre.

Reviews and comments

4.4 / 5
Based on 9 reviews

Reliability of the description
4.2 / 5
Ease of following the route
4 / 5
Route interest
4.9 / 5
Peillon06
Peillon06

Overall rating : 4.7 / 5

Date of your route : Apr 27, 2026
Reliability of the description : ★★★★★ Very good
Ease of following the route : ★★★★☆ Good
Route interest : ★★★★★ Very good
Very busy route : No

A magnificent route, though perhaps best avoided in the height of summer. You mustn’t be claustrophobic or suffer from vertigo or a fear of heights.
The descent to the footbridge and the peatland should be undertaken with caution.
The path along the cliff face beside the aqueducts is a little gem.
As clearly stated in the description, this is a difficult hike where you need sturdy footwear, water, a bit of a sense of direction, and to be careful. Walking poles will provide added security.
In fact, this is a hike featuring some beautiful, well-marked paths alongside trickier sections with loose stones (what on earth are the maintenance crews doing?), not a leisurely stroll.
Thank you for posting this online.
Finally, don’t miss a visit to the Baume Obscure cave, which is very pretty and run by a very friendly team.

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bernard bb
bernard bb

Thanks, Christian, for this comprehensive review
Best regards, B.

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User 7027871

Overall rating : 4.3 / 5

Date of your route : Mar 16, 2026
Reliability of the description : ★★★★☆ Good
Ease of following the route : ★★★★☆ Good
Route interest : ★★★★★ Very good
Very busy route : No

Hello
Thank you to the author of this unusual hike, which takes you through a variety of landscapes and, above all, offers spectacular views over the Siagne valley and the source of the Pare as you follow the Belletrud Aqueduct, built in 1906 – a superb panoramic view.
We followed the route described on Visorando to the letter, but we didn’t reach the elevation gain indicated on this hike?
The difficulty lies mainly in the distance rather than the elevation gain.
Kind regards
Christian PILORGET

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bernard bb
bernard bb

Hello Bucephale

This route has a second advantage: it exists.
Best regards, B.

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Bucephale
Bucephale
• Edited:

Overall rating : 4 / 5

Date of your route : Jun 10, 2025
Reliability of the description : ★★★☆☆ Average
Ease of following the route : ★★★★★ Very good
Route interest : Not used / Not applicable
Very busy route : No

A circuit with no interest other than the distance, which is nice (14 km, a good walk that still leaves time to go swimming in the river afterwards).
No pretty scenery, the tunnels are small and concentrated in a small part of the circuit.
No technical difficulties except for walking two-thirds of the way on stones and scree that roll under your feet...
In short, if you're hesitating between two hikes, go for the other one.
PS: the recommendation to take water is justified (at least 2 litres per person).

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bernard bb
bernard bb

Hello kikicobra65, thank you for this comprehensive review.

I wish you all the best in your preparations for the GR20.
Two hikes per week is ideal for good preparation. Personally, that's what I did for the GR20, which I completed in 15 stages. 15 kg is the maximum weight. Don't forget to allow for daily recovery.
Best wishes, B.

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kikicobra65
kikicobra65

Overall rating : 4.7 / 5

Date of your route : May 03, 2025
Reliability of the description : ★★★★★ Very good
Ease of following the route : ★★★★☆ Good
Route interest : ★★★★★ Very good
Very busy route : No

I completed this hike on 2 May 2025 in glorious sunshine.
The beginning of the route is fairly easy until you reach the summit of Rouyère.
After that, it gets a bit trickier in the sense that there are several sections where there is loose rock that could fall.
It is best to choose a dry period to avoid rock falls.
Then we arrive at the tunnels, which are marked with blue signs.
Be careful of the height, as specified in the description.
I am 1.80 m tall and with my rucksack (loaded with 15 kg, for training purposes for the GR 20 in July), it is impossible to pass through with it on my back. So I had to carry it by hand. When the distance is short, it's fine, but there's one that's about 100 metres long, which is a bit heavy, especially as one of the tunnels is almost vertical.
Anyway, I managed. Oh yes, I forgot to mention that a head torch is a must; there's no water inside.
Once you've gone through these tunnels, there's a fairly technical and tricky descent with quite a few rocks, so walking sticks are also welcome.
The descent to the footbridge is quite dangerous, so take care, but if you go slowly, you'll get there without too much trouble.
Finally, the climb up via the Siagne nest is hard on your feet, with quite a few crossings and a difficult climb up onto the bridge, as I couldn't find the marked path.
The end is very easy.
The difficult rating is well noted, but it remains one of the best hikes I have done, certainly because of its unusual nature, which gives it a special appeal.
Good footwear is essential.

Thanks again, Visorando.

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bernard bb
bernard bb

Thank you, Corbelli, for this review.
Best regards, Rando B.

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Corbelli
Corbelli

Overall rating : 4.3 / 5

Date of your route : Jun 17, 2024
Reliability of the description : ★★★★☆ Good
Ease of following the route : ★★★★☆ Good
Route interest : ★★★★★ Very good
Very busy route : No

A lovely hike with some unique features (tunnels, balcony paths, beautiful views of the Siagne valley).
Slightly technical, but this is normally noted in the hike description.
It should be noted, however, that there is a lack of signage indicating that you should take the path up to the right when you reach the large pipe in the stream bed.
An unusual and enjoyable hike.

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bernard bb
bernard bb

Thank you, papikatana, for your opinion.
You made me smile with your kind words, "Thanks again to the hermit who took the trouble to bring it into the world."
If you rated the route as "good", that's great.

The hike is physically demanding and the app remains useful.
Best regards, l'ovni man

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papikatana
papikatana

Overall rating : 3 / 5

Date of your route : May 28, 2024
Reliability of the description : ★★★☆☆ Average
Ease of following the route : ★★☆☆☆ Disappointing
Route interest : ★★★★☆ Good
Very busy route : No

It's very difficult to comment on this hike... The description is vague... Especially around "11" where you take the path with "blue markings". I found a steep descent marked in blue about 100 metres away, which descends steeply towards a beautiful waterfall. It is very dangerous. Obviously, I had left the trail but followed the blue markings. I wasted half an hour climbing back up... In fact, the path starts at the end of the wide road straight ahead...
After the tunnels, the long descent is very unstable in the scree... A real ordeal... It is dangerous and absolutely requires walking sticks (as specified). I lost the nails on my big toes there...
Finally, you cross the "malines" bridge and think that the way back will be easy. Not so, walking along the riverbed is a real torture with slippery rocks on wet moss and numerous obstacles... Endless... I only saw one cairn (?) and never found the exit... I had to climb just before the bridge... Where do you go in case of a storm when the riverbed fills up?
Well, having said all that, this hike is deserted and I only encountered wild goats without Manon... The scenery is nice, but nothing more. What remains attractive are the seven tunnels! Ah, I admit, I had never walked through such cool corridors with condensation dripping from the pipes... It's quite fun to walk through them, some go up, others go down...
Well, this hike is unclassifiable, long (6.5 hours for my trip), dangerous (in case of rain) but without any difficult climbs. It's best suited to experienced walkers with good, sturdy footwear...
Thanks again to the hermit who took the trouble to bring it into the world.

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bernard bb
bernard bb

Thank you, chrysarcane, for this review.
Best regards, B.

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chrysarcane
chrysarcane

Overall rating : 5 / 5

Date of your route : May 20, 2024
Reliability of the description : ★★★★★ Very good
Ease of following the route : ★★★★★ Very good
Route interest : ★★★★★ Very good
Very busy route : No

Thank you for the excellent description. A beautiful hike with open and magnificent landscapes.

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GdeG
GdeG

Overall rating : 5 / 5

Date of your route : May 18, 2024
Reliability of the description : ★★★★★ Very good
Ease of following the route : ★★★★★ Very good
Route interest : ★★★★★ Very good
Very busy route : No

A lovely, original hike that I'm glad I did.
Here are my comments:
As I am 1.85 m tall, going through the tunnels was even more difficult than expected. I had to hold my rucksack in my hand because it touched the top of the tunnel.
For the off-trail section, which is a rocky descent, I recommend at least one walking stick.
The vegetation blocks the path a little at the Deux Goules cave.
You can reduce the distance and elevation gain (by not doing any return trips) by starting the hike from the small car park at Saint Jean Chapel. However, the path from Baume Obscure to the GR is very pretty.
Thank you for posting it online.

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bernard bb
bernard bb

Well done on your humour, GdeG :-)

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