The San Lucano Valley (Belluno, Italy) was the core topic of the symposium: “L’armonia fra uomo e natura nelle valli dolomitiche” held in Agordo (Belluno) on the 12th and 13th November 2010. In this work the valley is analysed according to the following features: geological, geomorpholog-ical, structural, stratigraphic and ecological. The purpose of this paper is to review these features in order to establish the origins underlining the intrinsic geomorphodiversity of this unique area in dolomites. By walking along the river and observing landscape geomorphology or reading micro-and macroscale evi-dence on the mountainsides, the valley clearly reveals the keys to comprehending the geological history of dolomites from Triassic to present. A full list of geomorphosites has been appeneded in order to improve the scientific documentation of this valley.