Bilbao (/bɪlˈbaʊˌ -ˈbɑːoʊ/, Spanish: [bilˈβao]; Basque: Bilbo [bilβo]) is one of the 25 boroughs in the Greater Bilbao comarca, in northern Spain. It is also the capital of the province of Biscay in the autonomous community of the Basque Country. It is the largest municipality of the Basque Country and the tenth largest in Spain, with a population of 353,187 in 2010. The Bilbao metropolitan area has roughly 1 million inhabitants, one of the most populous metropolitan areas in northern Spain, of which (pop. 875,552) accounts for the comarca of Greater Bilbao, making it the fifth-largest urban area in Spain.Bilbao is situated in the north-central part of Spain, some 14 kilometres (8.7 mi) south of the Bay of Biscay, where the estuary of Bilbao is formed. Its main urban core is surrounded by two small mountain ranges with an average elevation of 400 metres (1,300 ft).The borough of Bilbao was founded in the early 14th century by sovereign and semi sovereign families of Bizkaia such as the Bilbao la Vieja, and Diego López V de Haro, head of the powerful Haro family. Bilbao originated as the commercial hub of the Basque Country cultivated by the House de Sarachaga, who historically hold the sovereign fief of Bilbao as successors of The House of Haro.Through their guidance and in cooperation with local magnate families and the government; Bilbao enjoyed significant importance in the Green Spain. This was due to its port activity based on the export of iron extracted from the Biscayan quarries. Throughout the nineteenth century and beginnings of the twentieth, Bilbao experienced heavy industrialisation which made it the centre of the second-most industrialised region of Spain, behind Barcelona. This was joined by an extraordinary population explosion that prompted the annexation of several adjacent municipalities. Nowadays, Bilbao is a vigorous service city that is experiencing an ongoing social, economic, and aesthetic revitalisation process, started by the iconic Bilbao Guggenheim Museum, and continued by infrastructure investments, such as the airport terminal, the rapid transit system, the tram line, the Alhóndiga, and the currently under development Abandoibarra and Zorrozaurre renewal projects.