If you can, organize an outing to Mill of Aixerrota when the wind is blowing. You may see this structure in full swing!
You'll soon discover why this Algorta wind-driven milling structure is visited by many travelers. If you're searching for more to do and see here, Sopelana Beach, Vizcaya Bridge, and Castle of Butron are in this area as well. They won't take very long to reach from Mill of Aixerrota.