A river of pebbles makes its way along the western slope of the Sierra de Meira. This is the Pedregal de Irimia, the moraine of an ancient glacier. If you listen carefully, you can hear the sound of the water bubbling out of the earth. These are the first trickles of the river Minho, a timid stream whose source is a mere 695 metres above sea level. As it flows down it is fed by dozens of springs; its flow strengthens considerably at the Lagoa de Fonmiñá. The sculpture dedicated to the god Breogán celebrates this. We have reached the plain, Terra Chá, a hypnotising land revered by poets where the river glides through wetlands.