Foz Côa Valley, the most important open air Palaeolithic rock art site, near Infercoa quarry
Infercoa natural slate is extracted from a Portuguese quarry, near the Foz Côa Valley, considered the most important open air Palaeolithic rock art site. Listed as a World Heritage Site by Unesco since 1998, this rock art carved into the rugged stones of the Côa Valley has been dated back to around 25.000 years ago.
