From the top of the hill at Serre overlooking the abandoned village of Esclangon, the view to the west opens up to one of the most beautiful geological panoramas in the Alps : the Vélodrome d'Esclangon, which is actually in the area of Tanaron.

This magnificent geological-cirque is formed by continuous deposits over almost 15 million years of sand, clay and then pebbles and boulders in a marine basin which then surfaced. The spectacular aspect of the site comes from the fact that the layers of sediments were deformed as they were deposited in a basin under compression. Then erosion did its work, highlighting the most resistant layers, such as the astonishing Facibelle Blade, an extraordinary blade-like, shard-like stone monolith that emerges from the forest.