National audienceThe small coastal valley of Conca in Grossa (Southern Corsica) is known for a long time for its numerous prehistoric and protohistoric sites among which several megalithic monuments. This valley is, however, relatively neglected from the scientific point of view, at least since the beginning of the twentieth century. It has only been investigated in the framework of a PCR regarding the megalithic Sartenais which point out the loss of an important quantity of information because of the difficulties in locating the sites and the disappearance of some of them, destroyed by the eruption of mechanized viticulture.The megalithic monument of Vaccil Vecchiu, classified by the Historical Monuments since 1862, has been known since im...