The thing about Zona 4 is that it sounds like a military sector, and in some ways it is, because it is a piece of ground that archaeologists have mapped and numbered for the sake of order. It lies about seven kilometres from Nerpio, in the same dry valley as its neighbours Zona 5, 6, 8 and 9, in the Sierra del Segura. The paintings of the area belong to the Levantine tradition protected by UNESCO since 1998, and they are known for their variety, with hunting scenes, animals and human figures that appear to dance.
The ride that includes Zona 4 also visits Úbeda, and the pairing is worth thinking about on the road. Úbeda is a Renaissance town in the olive plains of Jaén, an hour or more to the south-west, built in the sixteenth century by a small group of rich families who commissioned architects from Italy and Spain. It is a showcase of palaces, churches and plazas in golden stone. The painters of Nerpio worked on a more modest scale, but they, too, had a sense of composition.
The best of the ride is the stretch between Nerpio and Yeste, a road through high pine forest that is unusually quiet. The bends are medium and the gradients modest, and the scenery reminds you of the Alps in miniature, with long slopes of dark trees and open meadows. Wildlife is plentiful, with Spanish ibex on the crags, and if you stop for a moment in the early morning you may see deer at the forest edge. Cold winds can sweep across the plateau in the afternoon, so keep a windproof layer in the pannier.
For fuel, Huéscar is the place, thirty-eight kilometres away, and Yeste is the alternative at twenty-seven. Nerpio has shops and bars of a basic sort, and a lunch of lamb and migas is likely to be hearty. Do not underestimate distances in this part of Spain, and bring water for any walk to the shelter.