Best Urdaibai Biosphere Day Trips & Things to Do

Home to roughly 615 different species of plants and 318 species of animals, the Urdaibai Biosphere is a UNESCO protected ecosystem on the Bay of Biscay in Spain. The estuary, the heart of the biosphere, is one of the most important wetlands on the Iberian Peninsula for the diverse wildlife. The surrounding mountains are composed primarily of limestone and feature a variety of caverns across its surface. The area has been host to human settlers since prehistoric times, most notably in the Santimamine cave, where prehistoric cave murals and remains were found of multiple cultures.