The Côa River is a tributary of the Douro River, in central and northeastern Portugal. It is one of the few Portuguese rivers that flows south to north. It flows through the municipalities of Sabugal Municipality, Almeida Municipality, Pinhel Municipality, Figueira de Castelo Rodrigo Municipality and Vila Nova de Foz Côa Municipality, all located in the Guarda District.
Thousands of ancient carvings in stone were discovered in the Côa Valley in the 1980s and 1990s. These are of particular interest due to the high concentration of Paleolithic art, and because these carvings are found outside of caves, on rocks in plain sight: Jean Clottes, a prominent French prehistorian, had confirmed that "is the biggest open air site of paleolithic art in Europe, if not in the world".
The drawings attracted worldwide attention when plans to build a hydroelectric dam across the Côa Valley threatened to submerge them. Although hydroelectric development was already well underway, outcry from locals, the scientific community and the media led to dam construction being halted in 1995 after a change in the national government following elections. A significant proportion of the drawings in the Canada do Inferno area were already underwater by that time. The Côa Valley Archaeological Park, opened in 1996 , was declared a protected UNESCO world heritage site in 1998.