Mequinenza lies where the Segre river meets the Ebro, and the town you see today is not the one that stood here before the 1960s. When a dam was built downstream on the Ebro, the old town was flooded by the reservoir, known as the Mar de Aragón, and its people moved to a new settlement on higher ground. The old castle still sits above the water, and the reservoir stretches in long fingers between bare, ochre hills. It is a landscape both beautiful and a little melancholy, and the lake is famous among anglers for enormous catfish.
The riding is dry, open and a little bleak, in the way that Aragon can be. Roads here cut across steppe-like plateaus of rosemary and thyme, then drop to the reservoir shore with views over flat blue water and cliffs that glow orange at sunset. The surface is generally fine, with long gentle bends and little traffic. Wind is a regular companion, and in summer the heat comes up the valley like an oven door. Spring and autumn are better, when the air is clear.
Mequinenza has about two and a half thousand people, with fuel, a few bars and a small museum on the history of the coal mines, since the area was a lignite-mining district for generations. The town's fish restaurants serve river catfish and other Ebro fish, if you are curious. Fraga, seventeen kilometres away, is bigger, and has fuel, supermarkets and a good range of services, and it sits on the road toward Lleida and Zaragoza.
Fayón, across the water, has a similar story, with a new town and an old church tower sticking out of the reservoir in dry years. There is a certain charm in a landscape that has been so thoroughly reshaped, where the water hides a village and the hills lean over it. Park near the shore, walk down to the edge, and listen. If a fisherman is there, ask about the fish. It is probably an enormous one.