Lac du Trem walks

The fifth stage ofthe GR®52, where southern landscapes give way to mountain scenery. Challenging due to its elevation gain, this stage follows the old Italian border, where you’ll discover numerous military remains. Notably at Authion, where one of the last battles in France took place, resulting in the deaths of 273 French soldiers just a few weeks before the armistice of 8 May 1945. The views here are fabulous.

This itinerary allows you to discover the wonders of this valley. In particular, the famous engravings such as Christ, the Tribal Chief and the Altar Rock. But be careful, these areas are monitored!

A beautiful classic route on theGR®®52. As you progress along this three-part itinerary, you will appreciate the beauty of the lakes up to the Pas du Diable, then the very chaotic landscape at the foot of the Cime du Diable and Mont Capelet Supérieur. Finally, after the Baisse Cavaline, you will enter a more Mediterranean setting to discover the Authion massif, a historic site during the end of the Second World War.

Discover the Vallée des Merveilles by connecting the Vallée de la Gordolasque to the famous Refuge des Merveilles.

The first stage of a three-day trek in the heart of the Mercantour National Park, this route immediately takes the hiker into the high mountains via a little-used alpine route, away from the classic Pas de l’Arpette. On the itinerary: a steady climb up the Vallon des Verrairiers from the Gordolasque Valley, crossing the Pas du Trem (2,477 m) at the foot of the legendary Cime du Diable (2,685 m), then a long descent past a string of glacial lakes – Lac du Diable, Lac de la Muta, Lac du Trem, Lac Fourca – down to Lac Long Supérieur and the Refuge des Merveilles (2,130 m). A route combining the geological richness of the upper Gordolasque, breathtaking views of the Authion, Mont Capelet Supérieur and the Mediterranean on clear days, and a majestic entrance to the Vallée des Merveilles, a site listed as a Historic Monument. Characteristic wildlife: chamois, ibex, marmots.

Thissecond stage is the most alpine of the three. At the Refuge des Merveilles, you’ll admire the beauty of the landscapes, from the Cime du Diable to the Vallon des Merveilles. You’ll pass several lakes before descending into a more Mediterranean-style valley at the Pas du Diable. With the Redoute des Trois Communes in sight for much of the way, you’ll walk along the old border ridge, dotted with defensive structures. Near the Authion, numerous ruins will remind you of the end of the last war.

The Refuge des Merveilles can be a destination in itself or the starting point for a guided tour of the petroglyphs or other hikes. The climb to the refuge via Lac des Mesches takes 3 hours and 15 minutes (excluding breaks) and has the advantage of being accessible by car or public transport (see "Practical Information").

Starting from the Refuge de Nice, the fourth stage of this journey through the Mercantour is the shortest. Short but just as difficult. You’ll pass the Baisse du Basto, the highest point ofthe GR®52. You’ll cross over to Lac du Basto, then it’s the climb up the Baisse de la Valmasque, before descending into the Vallée des Merveilles.

This route, which runs parallel to the border, is dominated throughout by the large peak of Gélas, the highest summit in the area.

Second stage of the five-day Vievola–Saint-Martin Vesubie hike. ⚠️ 18/08/2026: Route amended at point 4.