Discovered in 1903 (second only to Altamira among Cantabrian caves with prehistoric artwork), the World Heritage–listed Covalanas cave is home to several breathtakingly beautiful red-hued paintings of deer and other creatures in an unusual dot-painting technique, executed around 20,000 BCE. With tour groups limited to eight people, visiting Covalanas is an especially profound and intimate experience. It's 2km south along the N629 from Ramales de la Victoria, then 650m up a steep, scenic footpath. Tours last 45 minutes; book ahead online.