The Urdaibai estuary

Estuary

An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....

 is a natural region and a Biosphere Reserve

Biosphere reserve

The Man and the Biosphere Programme of UNESCO was established in 1971 to promote interdisciplinary approaches to management, research and education in ecosystem conservation and sustainable use of natural resources.-Development:...

 of Biscay

Biscay

Biscay is a province of Spain and a historical territory of the Basque Country, heir of the ancient Lord of Biscay. Its capital city is Bilbao...

, Basque Country

Basque Country (autonomous community)

The Basque Country is an autonomous community of northern Spain. It includes the Basque provinces of Álava, Biscay and Gipuzkoa, also called Historical Territories....

. It is also referred as Mundaka

Mundaka

Mundaka is a town and municipality located in the province of Biscay, in the autonomous community of Basque Country, northern Spain. On the coast, Mundaka is internationally-renowned for its surfing scene....

 or Gernika estuary.

Urdaibai is located on the Bay of Biscay

Bay of Biscay

The Bay of Biscay is a gulf of the northeast Atlantic Ocean located south of the Celtic Sea. It lies along the western coast of France from Brest south to the Spanish border, and the northern coast of Spain west to Cape Ortegal, and is named in English after the province of Biscay, in the Spanish...

 coast, in the north of the Iberian Peninsula

Iberian Peninsula

The Iberian Peninsula , sometimes called Iberia, is located in the extreme southwest of Europe and includes the modern-day sovereign states of Spain, Portugal and Andorra, as well as the British Overseas Territory of Gibraltar...

. Urdaibai covers an area of 220 km² (84.9 sq mi) with some 45,000 inhabitants, most of them concentrated in the towns of Bermeo

Bermeo

Bermeo is a town and municipality in the sub-region of Busturialdea and the wider province of Biscay, part of the autonomous region of the Basque Country, in Northern Spain. Bermeo has 17,026 inhabitants and is the most important fishing port of the Basque Country. The town was founded in 1236 and...

 and Gernika. The territory is characterized by a hydrographic

Hydrography

Hydrography is the measurement of the depths, the tides and currents of a body of water and establishment of the sea, river or lake bed topography and morphology. Normally and historically for the purpose of charting a body of water for the safe navigation of shipping...

 basin of small streams that merge in a great salt marsh

Marsh

In geography, a marsh, or morass, is a type of wetland that is subject to frequent or continuous flood. Typically the water is shallow and features grasses, rushes, reeds, typhas, sedges, other herbaceous plants, and moss....

 surrounded by high sheer cliffs. The surrounding countryside is occupied by meadowland, oak

Oak

An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...

 groves, leafy woods and specially by plantations of fast-growing conifers (Pinus radiata). The coastal landscape is covered with Cantabrian

Cantabria

Cantabria is a Spanish historical region and autonomous community with Santander as its capital city. It is bordered on the east by the Basque Autonomous Community , on the south by Castile and León , on the west by the Principality of Asturias, and on the north by the Cantabrian Sea.Cantabria...

 woods of Holm Oak

Holm Oak

Quercus ilex, the Holm Oak or Holly Oak is a large evergreen oak native to the Mediterranean region. It takes its name from holm, an ancient name for holly...

 and Strawberry Tree

Strawberry Tree

Arbutus unedo, commonly called Strawberry Tree, Apple of Cain, or Cane Apple, is an evergreen shrub or small tree in the family Ericaceae, native to the Mediterranean region and western Europe north to western France and Ireland...

s.

In Urdaibai have been described 615 species of vascular plants and 318 species of vertebrates, 245 of which are birds.

The area contains remnants of the Prehistoric, Roman

Ancient Rome

Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....

 and the Middle Ages

Middle Ages

The Middle Ages is a periodization of European history from the 5th century to the 15th century. The Middle Ages follows the fall of the Western Roman Empire in 476 and precedes the Early Modern Era. It is the middle period of a three-period division of Western history: Classic, Medieval and Modern...

. Being particularly notable the Santimamiñe

Santimamiñe

Santimamiñe cave, Kortezubi, Biscay, Basque Country, Spain, is one of the most important archaeological sites of the Basque Country, including a nearly complete sequence from the Middle Paleolithic to the Iron Age....

 cave, that yielded remains from Mousterian

Mousterian

Mousterian is a name given by archaeologists to a style of predominantly flint tools associated primarily with Homo neanderthalensis and dating to the Middle Paleolithic, the middle part of the Old Stone Age.-Naming:...

 to Iron Age

Iron Age

The Iron Age is the archaeological period generally occurring after the Bronze Age, marked by the prevalent use of iron. The early period of the age is characterized by the widespread use of iron or steel. The adoption of such material coincided with other changes in society, including differing...

.

The economy is based on metallurgy

Metallurgy

Metallurgy is a domain of materials science that studies the physical and chemical behavior of metallic elements, their intermetallic compounds, and their mixtures, which are called alloys. It is also the technology of metals: the way in which science is applied to their practical use...

, fishing, farming and forestry. There is also an important tourist sector, centred mainly on the local beaches. Mundaka is specially appealing for surfers

Surfing

Surfing' is a surface water sport in which the surfer rides a surfboard on the crest and face of a wave which is carrying the surfer towards the shore...

around the world.

Geography

There are four distinct areas of interest in the reserve:

• The estuary.
• The shores.
• Holm Oak areas.
• Archeologic areas.

Geographically three distinct areas can be distinguished: The mountains, the marshes and the coast with its cliffs and beaches.