Dominating Dun and the Douctouyre valley, Pic Glalinié is the highest point of this loop, offering panoramic views of the Tabe massif and its emblematic peaks (Fourcat, Saint-Barthélémy and Soularac) and the Mirepoix region.

Dun has preserved the checkerboard structure of its origins and the remains of two fortified castles: Dun on the right bank, and Rogles on the left bank. The whole area was a feudal domain fought over by the Counts of Foix, Toulouse and Carcassonne. It fell into the hands of the de Lévis family at the same time as the seigneury of Mirepoix. Dun had also been a hotbed of Catharism, since Philippa, wife of Count Raymond-Roger of Foix and sister-in-law of the famous Esclarmonde, established a house of "parfaites" there in 1206.