The Côa rock art covers 17 km of the river valley and extends along the banks of the Douro, downstream of the confluence between the two rivers. A total of 194 different panels with Palaeolithic zoomorphic motifs have already been identified. Later prehistoric and historic periods, especially the Iron Age, are also represented. Settlement of the valley in Upper Palaeolithic times is documented by residential sites dating to the Gravettian, the Solutrean and the Magdalenian periods. Results of stylistic analysis, whose chronological predictions have been independently confirmed by superposition patterns derived from the figurative stratigraphies observed in the numerous palimpsests known, indicate that all these periods are also represented in the art. The outdoor location of the Palaeolithic art, the size of the territory, the number and aesthetic quality of the motifs represented and the almost uninterrupted continuity to the present of the artistic use of the region's rock faces concur to the uniqueness of this complex of sites. Accordingly, an Archaeological Park was established in the area, the construction of the dam that threatened to flood the rock art has been abandoned and the valley is to be included in UNESCO's World Heritage List.