Metropolitan Bilbao extends along the Nervión river estuary. Its component municipalities stretch for 12 km along both banks, housing a total population of around one million. Ports along the river estuary provided the basis for the development of Bilbao as a city, and in time the estuary became the backbone and focal point of the production and manufacturing companies which, until recently, were the mainstay of the city’s economy. The international recession which followed the second oil crisis in the late 70’s had serious knock-on effects in Spain, and particularly in the Basque Country, in the early 80’s. The heavy industry along the banks of the estuary reached a crisis point and went into decline.