About thirty years ago, the region near the north-eastern border between Portugal and Spain was a remote area visited, if at all, for its natural landscape. But in the late 1980s a spectacular discovery changed the way the Portuguese regarded these forgotten lands. The Côa Valley, located at the confluence of the Douro and Côa rivers, contains thousands of engravings of horses, bovines and other animals, as well as human and abstract figures dating from 22,000 to 10,000 BCE . This region, now a UNESCO World Heritage Site, is probably one of the largest open-air sites of Palaeolithic art in the world, and its importance to the local economy is now indisputable.
The steeply sloping site is characterized by the presence of slate, a sedimentary rock composed by several layers of mud and clay minerals. One of the most distinctive characteristics of the Art and Archaeology Museum is, paradoxically, that it blends in perfectly with that natural landscape: the local geology inspired the monolithic flat design, layered and compressed, camouflaged in the existing terrain. The museum reflects the chromatic palette of the geological layers visible in the local slate quarries with a skin that is both artificial and natural: concrete tinted with slate pigment and textured with moulds taken from local rock.
Apart from this 'materialized' continuity with the natural surroundings, an understanding of the topography and its constraints was crucial to the design. According to the architects, 'three main factors – topography, accessibility and programme – were confronted, generating the formal concept of the museum as an installation in the landscape'. The museum is located on the highest point of the site and to resolve the difference in height between the upper arrival and parking area and the lower museum entrance, the architects proposed a large platform, a place to stop and enjoy the magnificent views of the river, the surrounding hills and carved valleys before descending the slope to the museum entrance on the opposite side.
In such a strong natural landscape with almost no sign of human presence apart from the pre-historic drawings, the construction of a modern museum could have been a disaster of epic proportions. It is fortunate indeed that the architects have demonstrated sensibility and respect for this potentially vulnerable context, not imposing their talent, but understanding the importance of a low-profile intervention.