This work belongs to the BBVA collection. For several years it sat before the headquarters of the bank in Bilbao’s Gran Vía, in a continuous dialogue with the metro station designed by the architect Norman Foster, who assisted Chillida in selecting the sculpture's location. The title of the monumental steel piece makes reference to the sculptor's relationship with the material that proved fundamental throughout his artistic career: iron. In 1951, Chillida left Paris behind to set up home in Hernani. There, he rediscovered his roots and began working in Manuel Illarramendi's forge. Chillida forged metal using traditional techniques, each hammer blow constituting a direct battle with the red-hot iron. His discovery of this metal which was so closely linked with his homeland led Chillida to abandon figurativism in favour of abstraction. The iron path marked the start of a new aesthetic language and facilitated a new route for posing his questions about space. In this vertically-structured sculpture, a solid base rises up, and from its upper part four elements emerge, which delimit a space within them. The tension in this active space is created by the shapes surrounding it.