Cazorla and Segura — the high park where two rivers begin

• Parque natural — a protected landscape with villages still inside it. Cazorla is the largest of these in Andalusia.
• Nacimiento — the source of a river. Cañada de las Fuentes for the Guadalquivir; Fuente Segura for the Segura.
• Tranco — the reservoir that drowned a stretch of the upper Guadalquivir in the 1940s.

The relief is awkward on purpose: deep cuts, hanging valleys, ridges that force the road to climb and drop. Wild olive, kermes oak and juniper still hold the poorer slopes. A great deal of the visible forest is Aleppo and black pine, planted last century. Olive groves take the lower edges and the oil from these hills is the serious kind.

Spanish ibex use the rock. Red deer and wild boar use the woods. Mouflon and fallow deer were brought in. More than a hundred bird species are listed; griffon vultures on a thermal are the sight that stops the car. From Beas de Segura and Cortijos Nuevos the road skirts the park rather than diving into every track. Almond blossom in late winter breaks the olive green. That is the season to come if you want colour without heat.

• Cazorla, Segura y Las Villas Natural Park — map
• Guadalquivir valley — map
• Park tracks near Cortijos Nuevos — map

The dam at Tranco de Beas went up between 1929 and 1944 and made one of the bigger sheets of water in Spain. The upper Guadalquivir became a lake. People kayak, fish and take boats. The views that matter are from the road and from the Mirador del Aguilon. Isla Cabeza de la Viña sits in the water as a scrap of the old valley.

On a hill above the drowned river, the twelfth-century castle of Bujaraiza is half a story: stone on the ridge, the rest implied by the reservoir. Hornos stands on another spur looking over the same lake. The castle there holds the Cosmolarium, an astronomy centre that uses the dark park sky. Solana de Padilla is a viewpoint on that circuit, not a town you need to unpack. Santiago-Pontones is the inhabited scatter beyond it.

• Tranco reservoir — map
• Viewpoints above the lake — map
• Bujaraiza castle — map
• Hornos — map

Burunchel is the last village before the town of Cazorla takes over — a ledge of houses and a view into the first folds of the sierra. Cazorla itself is the base: castle rock, a tight centre, shops that sell boots and oil. Camp sites such as Puente de las Herrerias sit further in if you want to sleep under the pines rather than in town.

South of that gate, Peal de Becerro holds the Toya chamber, an Iberian tomb among the better preserved on the peninsula, and the ground of old Tugia. Quesada is the painters’ town: the Zabaleta museum for the local artist Rafael Zabaleta, and a small house-museum for the poet Miguel Hernandez and Josefina Manresa. Pozo Alcon is a quieter ledge on the way toward Granada province — walks and birds, not another museum.

• Burunchel — map
• Cazorla — map
• Peal de Becerro — map
• Quesada — map
• Pozo Alcon — map

Once you leave the Jaen core the park leaks into Granada. Castril is a rock town with a thirteenth-century castle and the Cerrada del rio Castril, a gorge walk along the river. The source of that river is a separate path. Huescar has the great church of Santa Maria la Mayor, Gothic turning Renaissance, and the Sierra de la Sagra standing off to the north like a private mountain.

Santiago de la Espada and Pontones sit high. Pontones takes its name from the old wooden bridges over the Segura. Near Fuente Segura, the Cueva del Nacimiento is among the oldest lived-in sites in the province. The river itself rises in these hills. That is the point of coming this far: not another viewpoint with the same vultures, but the start of a river that will run to Murcia and the sea.

• Castril — map
• Huescar — map
• Santiago de la Espada — map
• Pontones — map

A sensible day is Beas or Hornos around the Tranco, then Cazorla town. A second day takes Quesada or the Segura source. The old circular list — Beas back to Beas via every village — is a map, not a timetable.