The Cave of Altamira contains some of the most extraordinary art ever made by human hands. Painted by Magdalenian hunter-gatherers between roughly 36,000 and 11,000 years ago, the images cover the ceiling of a low gallery called the Polychrome Hall: bison rolling on the ground, horses, deer, and wild boar, rendered in red and black ochre with a skill and naturalism that astonished the world when they were finally accepted as genuine prehistoric work. The UNESCO World Heritage designation covers not just Altamira but 17 other painted caves across northern Spain.
The cave itself has been closed to general public access since 2002 to protect the paintings from the CO₂ and moisture introduced by visitors, which were causing significant deterioration. Access is now limited to a handful of researchers and a small weekly public lottery draw of five visitors — applications are made through the museum website and competition is fierce. For everyone else, the full-scale replica in the museum next door is the way to experience the paintings.