The protected area within the Natura 2000 Network called «As Catedrais«, in reference to this area of Ribadeo considered to be one of the most beautiful beaches in the world, occupies 297 hectares between the councils of Barreiros and Ribadeo, covering the coastal strip that stretches from Praia de Lóngara (Barreiros) to Penedo do Corvo (Ribadeo).
Thus, this Special Conservation Area (SAC) has a series of habitats and places of great geomorphological interest that make it unique and where interesting communities of animals and intertidal vegetation, dunes (Praia de Arealonga) and cliffs are found in its habitat. The latter is colonised by lichen vegetation and halophytic plants that are arranged according to their exposure to tidal splashes and strong sea winds. This group of vegetation is part of a protected habitat type of the Natura 2000 Network designated as «Cliffs with vegetation of the Atlantic and Baltic coasts.
As regard the dune systems are concerned, it is worth mentioning the «Praia de Arealonga» (Arealonga beach), a habitat of community interest. This beach is unique due to the presence of a peat bog that preserves the remains of an ancient forest 8000 years old. It is also possible to go bird-watching here, as it acts as a breeding ground mainly for seagulls and slime birds.
In the geological field, on the cliff of the beach of Punta Corveira, which is part of Lóngara, we can observe interesting lying downfolds that were formed during the clash between continents that gave rise to Pangaea about 350 million years ago. In addition, we can see how they appear cut by a dike or strip of a different rock called aplite.