History and Art 
The Town was founded in 1322 by Doña María Díaz de Haro " La Buena " (The Good Lady), on a settlement that had already been documented centuries earlier and was inhabited by seafaring folk living in the shelter of its natural harbour.
The foundation, whose charter bearing the signature of Doña María was lost years later, was ratified in 1432, by means of a Seal of Acknowledgement from Juan II of Castile, a document which still survives to this day.
Both documents granted the local people a series of privileges in the trade and transportation of goods, mainly wool and iron, as well as in fishing.
In the 19 th century, the industrialisation of the area bolstered its economy, reinforced by the arrival of the railway and the building of the Puente Colgante transporter bridge and the iron wharf, the Muelle de Hierro.
Its seaside location, together with its beach and spa, encouraged the new bourgeoisie to take up summer residence in Portugalete, building mansions alongside the river and on the coast.
Throughout the 20 th century, Portugalete continued to be a key location - a centre of trade and leisure on the left bank, the Margen Izquierda.