[13] Its climate is shaped by the Bay of Biscay low-pressure systems and mild air, moderating summer temperatures by Iberian standards, with low sunshine and high rainfall.

[37] The titles, the flag and the coat of arms are Bilbao's traditional symbols and belong to its historic patrimony, being used in formal acts, for the identification and decoration of specific places or for the validation of documents.

[45] Bilbao was one of the first towns founded in the fourteenth century, during a period in which approximately three-quarters of the Biscayan cities were developed, among them Portugalete in 1323, Ondarroa in 1327, Lekeitio in 1335, and Mungia and Larrabetzu in 1376.

[46] Diego López V de Haro, then third Lord of Biscay, founded Bilbao through a municipal charter dated in Valladolid on 15 June 1300 and confirmed by King Ferdinand IV of Castile in Burgos, on 4 January 1301.

This second charter established that the road from Orduña to Bermeo, at the time the most important trade route in the lordship, had to traverse the San Antón Bridge in Bilbao instead of the pass in Etxebarri, as it did until then.

In 1372, John I of Castile strengthened even more the city's position by naming Bilbao a free port and granting it special privileges concerning the trade of iron.

Beginning in February 1810, the city was under the command of Pierre Thouvenot, general of the French army and Baron of the Empire, who had become the head of the Military Government of Vizcaya, which included the three Basque provinces.

[56] The Carlist general Tomás de Zumalacárregui tried to take the city during the siege of Bilbao of 1835, but he was wounded during a battle near Begoña and died some time after in the town of Zegama.

The battle lasted until 19 June of that year, when Lieutenant Colonel Putz was ordered to destroy all bridges over the estuary, and the troops of the 5th Brigade took the borough from the mountains Malmasin, Pagasarri, and Arnotegi.

[63] On 26 August 1983 during the celebration of the local festivities known as Aste Nagusia, the estuary overflowed up to five metres in some areas due to the continuous raining, killing two people and causing important destructions in the city's infrastructure, with a total economic cost that reached 60,000 million pesetas (around €360 million)[65] Since the mid-1990s, Bilbao has been in a process of deindustrialization and transition to a service economy, supported by investment in infrastructure and urban renewal, starting with the opening of the Bilbao Guggenheim Museum (the so-called Guggenheim effect),[18] and continuing with the Euskalduna Conference Centre and Concert Hall, Santiago Calatrava's Zubizuri, the metro network by Norman Foster, the tram, the Iberdrola Tower and the Zorrozaurre development plan, among others.

It is surrounded by the municipalities of Derio, Etxebarri, Galdakao, Loiu, Sondika, and Zamudio to the north; Arrigorriaga and Basauri to the west; Alonsotegi to the south; and Barakaldo and Erandio to the east.

[74] Its main tributary is the river Cadagua, which rises in the Mena valley and has a basin of 642 square kilometres (248 sq mi), mostly lying in the neighbouring province of Burgos.

[78] This human intervention has also brought negative results in the quality of the water, after decades of toxic waste dumping causing a situation of anoxia (lack of oxygen), which almost eliminated the entire fauna and flora.

The current building was designed by the Spanish architect Joaquín Rucoba in Baroque style and was built in the former site of the San Agustín Monastery, which was destroyed during the First Carlist War.

In the 19th century the merge of Abando into the city brought along small neighbourhoods of farm houses and hamlets that were clustered close to the former municipality's town hall and the Mount Cobetas, such as Errekalde and Basurto.

The comarca of Greater Bilbao, in which the city occupies a central position, has a GDP per capita of €30,860,[105] higher than the Spanish and European Union averages.

Bilbao has been the economic centre of the Basque autonomous community since the original establishment of the Consulate of the Sea in the city in the 16th century, mostly thanks to the commerce in Castilian products on the town's port.

[121] In 1861, engineer Amado Lázaro projected an ensanche inside the then-municipality of Abando with wide avenues and regular buildings, that included the hygienists ideas of the time.

[128] Between 1890 and 1893 the first transporter bridge ("Puente Colgante") in the world on the Nervion river, between Portugalete and Getxo, was built by Alberto Palacio (architect and engineer) together with his brother Silvestre.

Since the deindustrialization process started in the 1990s, many of the former industrial areas are being transformed into modern public and private spaces designed by several of the world's most renowned architects and artists.

Another example is the Azkuna Zentroa, a wine warehouse built in 1909 and completely redesigned in 2010 by French designer Philippe Starck into a multi-purpose venue that consists of a cinema multiplex, a fitness centre, a library, and a restaurant, among other spaces.

Due to its scope, it is especially relevant the Bilbao BBK Live festival, which has been celebrated every year since 2006 and focuses on Basque, Spanish and international pop and rock music.

[152] The festivities begin on the first Saturday before 22 August, and during those nine days the city hall organises a series of cultural events of diverse kind, including concerts, stage plays, Basque rural sports and bullfighting, as well as nightly firework displays.

The central point of the festivities is the place around the txosnas, where the different konpartsak are reunited, organised by neighbourhood associations as well as cultural, social and political groups.

For the most part Bilbao shares its original gastronomy with that of the province of Biscay, including dishes such as bacalao al pil pil (cod fish cooked with olive oil, garlic and guindilla peppers), bacalao a la vizcaína (salted cod with Biscayan sauce, mostly made of choricero peppers and onions), merluza en salsa verde (hake fish with green sauce), chipirones en su tinta (squid served with its own ink), morros a la vizcaína (beef snouts with Biscayan sauce), revuelto de perretxikos (scrambled eggs with mushrooms) and desserts such as canutillos de Bilbao (puff pastries filled with custard or chocolate), Pantxineta (puff pastries filled with custard and almonds), rice cakes and bollos de mantequilla (butter buns).

Biscayan txakoli (Bizkaiko Txakolina) is a protected Denominación de origen for the white wine produced in the province of Biscay and it is usually served in Bilbao.

The line follows the estuary of Bilbao across the central districts of the city, starting in the Bilbao-Atxuri Station and connecting important areas like the Guggenheim museum and the San Mamés football stadium.

The original tram network started operations in 1876 and gradually expanded across the city to finally shut down in the 1960s due to being largely replaced by urban buses.

This public university, which has a presence in the three provinces of the autonomous community, has its main Biscayan campus in the municipality of Leioa, although the Technical and Business faculties are based in Bilbao.

[173] Athletic Bilbao was one of the founding members of the Spanish football league, La Liga, and has played in the Primera División (First Division)[174] ever since – winning it on eight occasions.