The Cíes Islands (; ) are an archipelago off the coast of Pontevedra in Galicia, Spain, in the mouth of the Ria de Vigo. They were declared a Nature Reserve in 1980 and are included in the Atlantic Islands of Galicia National Park (Parque Nacional Marítimo-Terrestre das Illas Atlánticas de Galicia) created in 2002. The archipelago The Cíes consist of three islands, Monteagudo ("Sharp Mount" or North Island), do Faro ("Lighthouse Island", or Illa do Medio, "Middle Island") and San Martiño ("Saint Martin" or South Island). Monteagudo is separated from the Morrazo peninsula by the North Canal while San Martiño is separated from the coast of Santoulo cape (mount Ferro) by the Freu da Porta Strait. The Do Faro island is linked to the North island by an accumulation of sand long known as Rodas beach, in the eastern side of the island. During high tide the sea flows between the islands in the western side and, blocked by the beach it fills the lagoon between the sandy area and the rocks. The highest peak is the Alto das Cíes () in Monteagudo. The islands formed by the end of the Tertiary, when some parts of the coast sank, creating the rías ("estuaries"). All three islands are the peaks of the coastal mountains now partially under the sea and are formed mainly of granitic rock. The land is mountainous with rough, nearly vertical cliffs of more than on the western side, and numerous caves (furnas) formed by erosion from the sea and the wind. The eastern side is less steep, covered by woods and bushes and protected from the Atlantic winds, allowing the formation of beaches and dunes. Atlantic squalls pass over the islands, unloading as they collide with the coast. Therefore, the Cíes receive more or less half of the rain than the rest of the Rías Baixas. Nature reserve Due to the high natural value of this area and to the deterioration it was suffering by human activity, it was declared a Nature Reserve in 1980. The level of legal protection varied until November 21, 2000, when the Galician Parliament unanimously agreed to apply for the status of National Park to the central Government. The Spanish Congress of Deputies signed a definite agreement in June 2002, creating the National Land-Marine Park of the Atlantic Islands of Galicia, formed by a number of archipelagos, islands and cays, namely the