The legend says that to enable the crossing of the river, the first kings of Portugal created, for the poor of that time, the so-called "Barges of God," free passages in places where people needed to travel between banks. That was the case in Caldas de Aregos, where Queen D. Mafalda placed a barge to allow reaching the thermal baths.

The boat that is currently making this trip was named Barca d'Aregos, thus evoking the barges that, dozens and hundreds of years ago, carried people from Caldas de Aregos to the other bank, where, in Tormes station, they would go by train to Porto or the Alto Douro, at a time when this was the only means of transportation available in the region.