Aizkorri-Aratz is not just about cheese; mining and ironworks are the protagonists of this stage. We ascend from Segura to Zerain, where close to our route are the ovens of Aizpea, used at the beginning of the 20th century to create the mineral from that extracted from the Mountain of Iron, a representative example of engineering in those days. We descend to Mutiloa alongside the Troi stream through a stretch full of mining remains. We go up to Aztiria, to subsequently descend again to Legazpia. It is here that this stage ends, in the famous and legendary historic foundry of Mirandaola.