The first images of this highway’s history were still in black and white. Still, the bridges and tunnels on the highway between Bilbao and Behobia have held up well through the arrival of color photography.

Built in the 1970s, what is now the AP-8 marked a milestone in Spanish civil engineering. It marked a before and after in Ferrovial’s history as the first time the company undertook a construction project of that size for transportation infrastructure.

The highway between Bilbao (one of Spain’s major industrial centers) and Behobia in Irún was also the Iberian Peninsula’s first major land connection with France. It coincided with the opening of the connection through the Mediterranean from Barcelona to La Junquera. The over 100 kilometers of motorway built in the ’70s was a giant leap forward for the Basque Country and much of northern Spain.

Bringing this project to life entailed excavating over 25 million cubic meters of soil and rock. More than half a million cubic meters of concrete and just as many tons of asphalt agglomerate were used. Three bridges and 23 viaducts were also built. Facilities were set up to make piles and beams near the construction site. The work involved techniques and technologies that were still cutting-edge in those years.

Today, the highway between Irún and Bilbao has extended beyond the Basque Country. It’s part of the Cantabrian highway, a road connecting the entire northern coast of Spain from Lugo to the French border.