This route offers the combination of spectacular views and history that is hard to find. Most of the riding is on high alpine gravel roads, but there is a challenging singletrack climb in the middle. The whole ride is well above the tree line, so you'll have spectacular views into Italy or France (and at times both). In case the spectacular natural vistas aren't enough, there are three impressive stone fortresses from the early-20th century in various states of ruin along the way.
To access this trail, you'll have to drive literally up a ski run from Limone Piemonte via Panice Soprana on the Italian side. It's not the kind of thing you probably do everyday, but it's fully asphalted to the top and can be done in a normal car. There is a mountain hut (Chalet le Marmotte) and large parking area just below the Col de Tende Pass. It is not recommended to drive up from the French side.
Because of the altitude you've got to consider that the trail is likely only snow free from early July through early September.
From the parking lot, take the branch to the right to travel about a 1/2 mile to the Col de Tende (Tende Pass). From the pass, do not continue down the mountain (it is a long way back up!), but make a sharp left towards Fort Central to follow the Les Trois Forts de Montagne (The Three Mountain Forts)
gravel road. You can ride through/walk around the fort and its accompanying barracks and you'll enjoy an awesome view down into France.
Once you've finished, continue on and the path will merge with the Strada ex-Militare Colle di Tenda (Former Tenda Pass Military Road)
for about 0.3 miles which straddles the border at this point.
When you reach the fork at about 1.2 miles, keep to the right to begin the 100 m (340 ft) climb to the second fort, Fort Tabourde. Along this segment, you'll enjoy excellent views of the Vallée de la Roya (Roya Valley) and the 50 or so switchbacks for the old road through Tenda Pass from the French side.
After visiting Fort Taubourde, you'll climb again until 4.2 miles where there is a short respite as the trail follows the border again. Then it's another short 75 m (250 ft) climb over a half mile. Here the trail intersects the Cime du Bec
singletrack. Save this for the return trip and instead continue along the road to visit Fort Pépin, which also offers commanding views of neighboring peaks and France below.
Backtrack for a short distance from the fort to take the Cime du Bec
singletrack. This is a fun, continuous, two-mile descent to the Col de la Perle (Perle Pass). First, this trail offers sweeping views into Italy; then it follows the border for a short distance and you'll have sweeping views into Italy and France; finally it switches to the French side and you'll have sweeping views into France. The last half mile of singletrack down to the pass is a pretty steep descent and with a significant cross-slope at times but it's pretty rideable.
When you get to the pass, turn left and then immediately left again onto the Strada ex-Militare Colle di Tenda (Former Tenda Pass Military Road)
. You'll coast down to a small alpine lake and then begin one final, very gradual, climb over the next two miles.
During this climb, you'll travel through a high alpine valley. At the top of this climb, continue on the main gravel road to begin a steep mile-long, switchbacked descent down to the upper station for a ski lift. From the ski lift, you have another 1.5 miles of descent down to your car.
Further west from the Colle di Tenda loop, there are three additional forts that you can visit if you've got more time and energy.
The Italians built a large network of military roads along their mountainous borders with France, Switzerland, and Austria-Hungary (now Austria and Slovenia) during the time of the first world war. Many of these roads are now maintained for recreational pursuits.
The Col de Tende has been an important trade route since ancient times although a tunnel now runs beneath it. The Colle di Tenda loop allows you to visit Fort Central (formerly Forte Colle Alto), Fort Tabourde (Forte Taborda), and terminating at Fort Pépin (Forte Pepino). The Italians were anxious to defend it against invasion, but they lost and the forts are now all on French territory.