Circuit des 25 Bosses

The 'Circuit des 25 Bosses' (The 25 Bumps) is located in the Massif des Trois Pignons, on the western edge of the Forêt de Fontainebleau. Originally established in the 1970s as a training ground for alpinists, this technical 16km loop remains one of the most demanding day hikes in the Île-de-France region. The trail requires hikers to cross 25 distinct sandstone ridges, involving frequent scrambling over boulders and navigating deep sandy paths. It is an intense physical challenge characterized by constant elevation changes and a unique ecosystem of maritime pines and white sand dunes. Note: Compiled from public sources — not a field report.

One of the most frequented day hikes from El Chaltén, the route to Laguna Torre leads to a glacial lake at the base of the Torre massif. The 18 km out-and-back trail follows the Fitz Roy River valley, moving through sub-antarctic forests of ñire and lenga. The terrain is primarily well-maintained gravel paths and packed dirt, with a short initial ascent followed by mostly level walking through the glacial valley. The destination offers direct views of Cerro Torre (3,128m) and the Adela range, with icebergs frequently calving from the Torre Glacier into the lake.