Cuerda del Pozo is the big inland sea of Soria — pine forest on every shore, the Sierra de Urbión behind, and the young Duero filling it cold off the granite. The locals sail and swim here, and on a hot Castilian afternoon you can see why. For the fly fisher it is warm-water sight-fishing country: carp cruise the shallow bays and the flats, and a beetle or a slow nymph dropped ahead of a feeding fish is the whole game. It is run as special-regime water so you can fish it from a boat, which opens up the points and the drowned river bends. There are pike and zander in here as well — both non-native, both with their own rules — but the carp on a warm, bright day are reason enough to come.

• Reservoir
• Granite