Unesco declared Urdaibai a biosphere reserve in 1984. It comprises a large marsh formed by the river Oca as it flows into the sea, thereby providing a rich source of food for a large variety of seabirds. Inland, Gernika is situated at the vertex of this enormous delta. Gernika is the town immortalised by Picasso in his painting of the bombing raids perpetrated during the Civil War. It is also the town where in ancient times the Lords of Vizcaya took their decisions in the shade of a large oak tree, the Oak of Gernika.
Nearby, you can visit the Santimamiñe caves, well known for their prehistoric paintings. And on the coast, you can visit Elantxobe at one end of the river estuary and Bermeo at the other. Both towns have a long seafaring tradition and celebrate festivities in remembrance of centuries-long disputes over the island of Izaro, which is situated halfway between them.
You should not forget to take a walk through the forest of Oma, where the Basque artist Agustín Ibarrola has created picturesque shapes and figures in several colours in harmony with this natural space. In short, Urdaibai represents an important part of the history, culture and natural heritage of the Basque Country.