Deep in the Sierra de Segura in the northeast of Jaén province, close to where the Segura river is born, the Engarbo rock shelters hide a few small painted figures under limestone overhangs. They belong to the great serial UNESCO listing of Levantine rock art, prehistoric paintings found along the mountains of eastern Spain, with stylised humans and animals in red ochre that have survived thousands of years of sun, frost and goats. The shelters are modest and fragile, often fenced, and visits usually need to be arranged locally, so treat them as a reason to explore this remote corner rather than a guaranteed sight.
And remote it is. The area falls inside the Sierras de Cazorla, Segura y Las Villas Natural Park, one of the largest protected areas in Spain, a vast sea of pine-covered ridges, deep valleys and limestone cliffs. Black pine and Aleppo pine cover the slopes, griffon vultures circle overhead, and ibex and deer are common enough that you should ride the bends expecting one standing in the road. The Segura rises from a spring near Pontones and becomes the river that later waters the orchards of Murcia; up here it is clear and cold.
The roads are narrow, often single carriageway with crumbling edges, and twist relentlessly through the mountains. There are spectacular stretches over passes and past reservoirs, but also fallen rocks, gravel washed across bends after rain, and blind corners where a truck loaded with timber appears without warning. Plan for slower progress than the distances suggest. Spring and autumn are lovely; midsummer is hot in the valleys but bearable up high, and winter can bring snow above a thousand metres.
Services are scarce. Nerpio, Segura de la Sierra and Orcera are small mountain villages; Segura de la Sierra in particular is worth the detour for its castle perched on a crag and its whitewashed streets. For reliable fuel, plan around the larger towns, and Huéscar, about thirty kilometres away, is the nearest place of eight thousand people. Fill the tank whenever you see a station. Village bars serve grilled meat, migas and local olive oil of extraordinary quality, and the water from the mountain fountains is usually clean and cold.