The Urdaibai Estuary is a biosphere reserve and UNESCO World Heritage site located along the coast of the Bay of Biscay in northern Spain. It supports a high level of biodiversity with over 600 plant and 300 vertebrate species, including 245 bird species. The estuary also contains important archaeological remains dating back to prehistoric, Roman, and medieval periods, such as the famous Santimamiñe cave.

1. Urdaibai Estuary

2. The Urdaibai Estuary is a natural region and a biosphere
reserve of Biscay.It´s located in the Bay of Biscay coast, in
the north of the Iberian Peninsula. It was declared World
Heritage by the UNESCO in 1984.
In Urdaibai there have been described
615 species of vascular plants and 318
species of vertebrates, 245 of which are
birds.
The area contains remains of the Prehistoric,
Roman and Middle Ages; such as the famous
Santimamiñe cave.