Ulldecona sits at the southern edge of Catalonia, in the Montsià district, where the Ebro delta flattens out to the east and the Serra de Godall rises in a blunt wall behind the town. The Abric d'Ermites IIIa is one of a group of rock shelters in the hills here, painted in the Levantine style and part of the UNESCO listing for the rock art of the Mediterranean basin. The paintings are red, simple and old, showing hunters and animals, and the group in this range is well regarded for the quality of the figures that survive.
The shelters are reached on foot, and the sites are managed locally. There is a visitors' route and an interpretation point in the area, but opening times and booking arrangements change, so check before you set off. In the meantime the Serra de Godall is a reward on its own, with rocky ridges, pine, rosemary and the sort of limestone that holds heat all afternoon.
Getting in is not difficult. The roads between Ulldecona and the hills are narrow, lightly used and lined with olive terraces. Olives are the money crop here, and the oil from the Terres de l'Ebre has a protected name. Expect gentle climbs, a few tight bends near the sanctuary and the sort of surface that has seen too many farm tractors. Ulldecona has around six thousand people, with fuel, a bakery and bars where a small coffee is the standard opener. The village of Santa Bàrbara, a little to the south, is smaller but handy.
The season matters. In July and August the heat is serious and the Mistral can swing across the delta in winter, making the coastal roads cold and blustery. Spring is the sweet spot, with wildflowers in the scrub and cool mornings. In autumn, when the olive harvest begins, the roads fill with small trucks and the smell of crushed fruit drifts from the mills. A half-day here, with a walk and a lunch of rice and seafood from the delta, is a very good way to spend a weekend.