La Garma is a low limestone hill a few kilometres inland from the Bay of Santander, green with meadows and oak scrub, the sort of rounded Cantabrian hump you might ride past without a second glance. Inside it lies one of the most important prehistoric caves in Europe. Found by chance in the 1990s, the cave of La Garma contains not just paintings but preserved living floors from the Palaeolithic: hearths, bones, tools and the outlines of shelters left exactly as they were when a rockfall sealed the entrance thousands of years ago. It forms part of the UNESCO site of the Cave of Altamira and Palaeolithic Cave Art of Northern Spain.
Precisely because it is so fragile, La Garma is not a show cave. Access is extremely restricted, mostly for researchers, and you should not expect to go inside. For a taste of what lies underground, the caves of Monte Castillo near Puente Viesgo, about an hour inland, are open to visitors and very impressive, and Altamira itself has a full replica and museum near Santillana del Mar.
The area around is coastal Cantabria at its most relaxed. Ribamontán al Monte and the neighbouring villages are farming country, with dairy cows, stone houses with wooden balconies and big tracts of eucalyptus. To the north, the coast breaks into cliffs and long sandy beaches, with Somo a well-known surf spot facing Santander across the bay. To the east, Santoña is famous for its anchovies, packed by hand in olive oil, and a tin of them makes a good souvenir.
The riding is short and pleasant rather than epic. Local roads twist between hills and villages, with surfaces mostly good but often damp, since this coast gets rain all year round and the bends under trees stay slick. The bigger rides lie inland: the passes into the Cordillera Cantábrica, such as the routes up the Pas and Miera valleys, offer steep, tight climbs and remote high pastures.
Santander, about twelve kilometres away as the crow flies, is the place for everything practical, though the small towns nearer by have fuel and bars too. A plate of rabas, fried squid, with a glass of cider or a cold beer is the local way to finish a ride.