Playon de Bayas, with nearly 3 km in length, is the longest beach of Asturias. Its formation is not random. It is due to the large amount of sediment carried by the Nalon River, which drains about two thirds of the Asturias region, which is located west of the beach. The dominant longshore currents in the Bay of Biscay, west to east, dragging these sediments making them trip over the Cape highlight Vidrias and depositing them on the beach of Bayas, leading to the formation of an important dune.