 At the southern exit of the tunnel, after a 50-metre walk, from a clearing a trail penetrates almost unnoticed up the forest on the right, so beginning a 30-odd minute uphill struggle (not in vain is it dubbed "Kalbario Bidea", 'Calvary Trail') with loose pebbles all along.At this point, an opening affords a beautiful view onto the north and the trail cuts along the verge of several limestone cliffs on its way north-west.In another 30 minutes, the Aizkorri summit may be attained.