Starting point 5 km away from Otzaurte (Zegama). leave the car in the parking of Aldaola-Ubier (you can search in google maps) where there is also a panel with explanations. From here begins the climb to the highest peak of Euskadi, a slope with 3 alternatives. – Zegama-Aizkorri marathon path. – Calvario or Mandobide path. – Alaveses path. In this case we are going to make a circular route going up from Calvario path and down from Alaveses path. On the route Take the dirt track (you will see it with a sign that says Sandratiko Koba) and follow the white and red signs to San Adrian tunnel. You will pass through the house of the Mikeletes, an old abandoned mountain hut. Before arriving to the famous tunnel of San Adrian the path joins the Saint Jaques way. Once we cross the tunnel, the middle age road appears. A highway from the middle age built stone to stone – 1000 meters high – in an inhospitable place! Don’t lose your attention in this point where this medieval motorway is turning, we must turn off to begin the ascent that leads to Santo Cristo hermitage on the same top of Aizkorri. Do not worry, it is not so hard! This path is introduced in a large beech forest that will shelter us from the sun. Enjoy this landscape. The path is marked with yellow paint marks and typical mountain stone milestones. Arrival point, at the top, you can see a free opened mountain hut (you can spend the night all year), the chapel of Santo Cristo and the Aizkorri summit commemorating cross. To get back we will select the Alaveses path that in the beginning coincides with the same route we have climbed but goes to the right following some red paint marks to Zalduendo. We will continue the descent until we reach GR-283, point called Linategieta, where we will turn left. We will have to follow the GR-283 to get back to the middle age road that we have seen at the exit of the tunnel. And from this point we already know the path we have to follow to descend to the car. During your walk, you will see: 1. San Adrián tunnel. A magical and historical place. 2. San Adrián’s hermitage. It’s actually inside the tunnel! 3. Medieval causeway. It used to connect Castilla to the coast during the Middle Ages. It is part of the Camino de Santiago. 4. Santo Cristo de Aizkorri’s hut and hermitage. Only 10 metres from the top, you will find this shelter and the hermitage. Spend the night there, if you need. From here you can easily get to the top of Aizkorri. 5. Top of Aizkorri. We find ourselves at the top that gives its name to the highest mountain range in the Basque Country. Next to this peak, we can find the highest peak of the Basque country but is Aizkorri the most famous and the one who is accepted like the highest summit. From here we will have incredible views in case of a clean day.